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Cooler Master

Cooler Master MasterBox Q300L Micro-ATX Tower with Magnetic Design Dust Filter, Transparent Acrylic Side Panel, Adjustable I/O & Fully Ventilated Airflow, Black (MCB-Q300L-KANN-S00)

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Availability: Only 5 left in stock, order soon!
Fulfilled by Amazon
Arrives Tuesday, Apr 29
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Style: Q300L


Features

  • Magnetic Dust Filters: The unique pattern of the dust filter adds a distinctive appearance to the case.
  • Components Clearance: Accommodates CPU coolers with a max height of 159mm, GPU cards up to 360mm, and PSU up to 160mm in length.
  • Versatile Cooling: Maximize cooling performance with a 240mm liquid cooler and 5 fans.
  • Modular I/O Panel: You have the flexibility to adjust its position at the front, top, or bottom on both sides
  • Edge-To-Edge Panel: Show off your meticulous build through the transparent side panel with pride.
  • Open Thermal Design: The perforated design on all sides promotes optimal airflow and heat dissipation
  • Ample Interior: Explore ample interior space for Micro-ATX or Mini-ITX motherboards, ensuring easy and future expansion

Description

The Master Box Q300L is your straightforward option in the lineup of the brand new Master Box Series from Cooler Master. A Series that might be small in size but excels in functionality and modularity without compromising on the thermal performance. Although the size wouldn't tell, the Master Box Q300L supports a standard ATX PSU which we don't see often in the market with this size. Based on the different system setup, the I/O panel can be adjusted to six different locations, three options at each side of the case. You can decide which setup fits your system best. Due to the cube design of the frame and special pattern design on the magnetic dust filter will make the chassis stand out from the rest. The combination of a practical design and the unique customizable outlook makes the Master Box Q300L The perfect choice for office and home.

Brand: Cooler Master


Motherboard Compatability: Micro-ATX and Mini-ITX


Case Type: Mini-Tower


Recommended Uses For Product: Gaming


Color: Black


Material: Alloy Steel, Plastic


Power Supply Mounting Type: Bottom Mount


Cooling Method: Air


Model Name: Q300L


Item Weight: 480 Grams


Wireless Type: ‎802.11a


Number of USB 3.0 Ports: ‎2


Brand: ‎Cooler Master


Series: ‎Q300L


Item model number: ‎MCB-Q300L-KANN-S00


Item Weight: ‎1.06 pounds


Product Dimensions: ‎15.39 x 9.06 x 15 inches


Item Dimensions LxWxH: ‎15.39 x 9.06 x 15 inches


Color: ‎Black


Department: ‎Computer Cases


Manufacturer: ‎Cooler Master


Country of Origin: ‎China


Is Discontinued By Manufacturer: ‎No


Date First Available: ‎December 5, 2017


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Apr 29

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Cheap, light, well designed.
Style: Q300L
Review Image by Penicillin Penicillin
The media could not be loaded. Fantastic case for the money. I built a "console" PC to exclusively play PC games on large screen TV. This fits the bill. Added three fans for good air flow with coarse screws, hidden by the magnet shields. Micro ATX fit like a glove, with regular size PSU and large GPU, all fit great. Case is super light. Also, lots of hiding space in the back, but I wouldn't try IDE HDDs, only SSDs and smaller. Great case! ... show more
Reviewed in the United States on March 28, 2025 by Penicillin Penicillin
    • Amazing Case For an Amazing Price! (Model: Q300L)
Style: Q300L
So first I'd like to state that this review is specifically for the Q300L model. Amazon does this annoying thing where they mix all the reviews of all the models together and I can't stand it so I'm just stating the model flat out. I just built my 10 year old nephew’s PC using this case and I have to say that I was very surprised at how much I loved building in this case. Originally I bought the Compucase HEC HX300 case for 30$ from Newegg and I was just frustrated at the lack of air flow from that case. It only had room for one fan which was the back exhaust and that's it. It didn't even have holes for the power supply's intake fan! It was my fault for not researching enough and buying something so cheap. Then I did a little research and came across this case. It is only 50$ but has everything I want. I've seen PC builders on youtube build with this case and they all had great things to say. So the first thing I like about this case is obviously how much airflow it allows. It's an interesting design because there are holes all over the top, all over the bottom, and all over the front and you can install 4 fans if you wanted to (2 up top, 2 in front, 2 in bottom) in addition to the included exhaust fan at the back making it support up to 5 fans! Now with all those holes you might be thinking this is going to be an ugly case but as you'll see in the pictures this is not the case (pun intended) and it has very sleek looking dust filters to cover the top, front, and it’s not obvious from the picture but it has a filter on the bottom as well. I was pleasantly surprised to see that the filter is magnetic which made removing them to install my fans a breeze (pun intended). I also imagine cleaning them when they get dirty will also be very simple. You can simple remove them and just rinse with water. One tip when installing fans is that since there’s air holes all over, they actually made a very small indentation around the holes that you should screw in your fans. These “guides” are hard to notice but if you look closely you’ll see them. They have space for 140mm and 120mm fans depending on whatever you want. Air is able to easily flow through the filter so my air flow issues were resolved! The case also looks very nice in my opinion. I have the black model just because that’s what my nephew wanted but in review videos I’ve seen, the white one looks very nice as well. Cable management at the back is pretty good too and the case comes with a lot of zip ties. The filters I mention above are also very aesthetically pleasing. The power button, 2 USB ports, headphone jack, and speaker jack are on the side which I don’t mind. The interesting thing is that this IO panel can be unscrewed and moved to the other side which is nice. The clear side panel is acrylic but it’s a 50$ case so it’s fine. It doesn’t look bad at all. There’s also room in the cable management area for a 3.5” hard drive and 2 SSD’s inside the main area which is very good. Overall the case was pretty simple to build in. It’s designed very well to maximize airflow while looking great. I think this is an excellent case especially for the price. If you’re in the market for a cheap but good PC case, then you my friends have stumbled on a cheap but GREAT PC case. I would highly recommend this case and am willing to do even more expensive builds with this case in the future. One final note I’ll add, I built my nephew’s pc with a Ryzen 5 1600 processor and RX 480 gpu reference model targeting 1080p gaming and the heat in my old case with that one exhaust fan was reaching around 87 degrees C. After I added two intake fans in the front and one exhaust fan in the top along with the back exhaust fan that comes with this case my temperatures went down into the mid 70’s while gaming which is great. If you want looks as well as functionality for a great price, go with this case. ... show more
Reviewed in the United States on June 25, 2020 by Fa
    • Pretty Good
Style: Q300L
I was looking for a small mATX case to use with some older parts that I had in storage (I will list all the parts at the end for reference). So far it's worked great and I didn't really run into any major issues. I like how compact the case is and I was able to fit it under a small table. The computer is for light gaming and web browsing, so thermals have not been bad. Putting all the components together in the case was pretty straight forward. I found it a lot easier to work with than a small ITX or even a full ATX build. I didn't install any fancy or exotic parts (AIO/Water Cooling) and kept it simple, which I feel helped a lot. I like the dust filters that come with the case and the design on the filters give it a nice look. Since I am using a simple CPU (9400F), fan noise is non-existent since the processor doesn't generate a lot of heat. I'm using some Corsair RGB fans (x2 in front panel/x2 top of case), which look great and have them configured to silent in iCUE. There are a few issues so far with the case: 1) Stock outtake fan stops spinning randomly. I have it connected to the motherboard and have set the fan to full speed, but it does not fix the issue. I've also tried other fan headers on the board, but the fan continues to stop spinning. Not a big deal since a basic case fan is inexpensive, so I will be replacing it. 2) The Plexiglass can scratch easily if your not careful. I debated taking off the plastic film for this reason, but decided to remove it in the end. Glass would have been better, but for the price, you really can't complain. 3) Expansion slot covers are attached to the case, so removing them can be a little tricky. I ended up bending one of the slots a little bit, but was able to fix it by bending it back into place carefully. Finally, the only other thing that would have been nice is to have an all-in-one front panel connector. This would definitely help inexperienced builders to easily connect the front panel ports/power to the board without much struggle. Overall I'm happy with the case and do recommend it for anyone looking for an inexpensive mATX build that will look great. PC Specs: AsRock B365M Pro 4 Motherboard i5 9400F 8GB TeamGroup RAM 2133Mhz (two modules) RX 570 4GB TeamGroup SSD EVGA 650W Power Supply ATX (non-modular) ID Cooling Low-Profile CPU Fan (IS-47-XT) x4 Corsair SP120 RGB Fans with Commander Core ... show more
Reviewed in the United States on November 28, 2023 by InZane4all

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