Cooler Master
MasterBox Q300L Micro-ATX PC Case – Compact mATX Computer Case with Magnetic Dust Filters, Modular Adjustable I/O Panel, Perforated Airflow Design, 1 x 120mm Pre-Installed Fan, Black
*Price sourced from Amazon.com. Last updated 2026-05-21. Price and availability subject to change.
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…
SpecPicks Verdict
SpecPicks classifies Cooler Master MasterBox Q300L Micro-ATX PC Case – Compact mATX… as a solid pick with broad community endorsement in the pc cases category, based on 13,902 verified Amazon reviews and our ranking model that weights rating × review-volume × price-fit. Cooler Master's positioning sits comfortably above the category median. Use the Compare tool to put it side-by-side with two or three close alternatives before clicking through to Amazon.
Common buyer scenarios for pc cases of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the Amazon listing before purchase. Prices, stock, and Prime eligibility update directly from Amazon's catalog and may have moved since this page was last verified.
Pros & Cons
Pros
- ✓ Highly rated — 4.5★ average across customer reviews
- ✓ Large, well-vetted feedback pool (13,902 reviews)
- ✓ Versatile Cooling Maximize cooling performance with a 240mm liquid cooler and 5 fans.
- ✓ Backed by Cooler Master's warranty and support channels
- ✓ Ships via Amazon with Prime eligibility and the standard returns policy
Cons
- ✗ Confirm socket / form-factor / power-rating compatibility against your build before ordering
- ✗ Price, stock, and Prime eligibility update from Amazon and may have changed since this page was last verified
Key Features
- Ample Interior Explore ample interior space for Micro-ATX or Mini-ITX motherboards, ensuring easy and future expansion
- 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
Full Specifications
| UPC | 884102095313 884102038006 |
|---|---|
| ASIN | B0785GRMPG |
| Brand | Cooler Master |
| Color | Black |
| Material | Alloy Steel, Plastic |
| Case Type | Mini-Tower |
| Model Name | Q300L |
| Item Weight | 480 Grams |
| Manufacturer | Cooler Master |
| Model Number | Q300L |
| Built-In Media | 1 computer case |
| Cooling Method | Air |
| Item Type Name | grocery |
| Number of Fans | 3 |
Ready to buy?
Cooler Master MasterBox Q300L Micro-ATX PC Case – Compact mATX Computer Case with Magnetic Dust Filters, Modular Adjustable I/O Panel, Perforated Airflow Design, 1 x 120mm Pre-Installed Fan, Black is available on Amazon with Prime shipping and the full Amazon returns policy. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
*Price sourced from Amazon.com. Last updated 2026-05-21. Price and availability subject to change.
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