Define S Window

The Fractal Design Define S borrows its appearance, sound dampening technology, and support for a wide variety of components from the widely popular Define Series, while featuring a streamlined internal layout

  • Designed for silent computing and great airflow/cooling capabilities
  • Innovative internal layout with straight airflow paths
  • Extensive water cooling support for its size


View specifications


The Define S case is packed with intelligently designed enthusiast-oriented features delivering a silent case with powerful and expansive air and liquid cooling support. The modernized layout omits the optical drive bays, focusing on a clear straight airflow path and uncompromising water cooling support. The Define S case reaches the highest level of silent computing through strategically placed dense sound-absorbing material, multiple ModuVent™ fan vent covers and finely tuned Dynamic Series fans.

Extensive cooling support and designed for silent computing

Optimally designed for silent computing, while not compromising on airflow and cooling capabilities
  • Innovative internal layout, providing a straight airflow path to the CPU heat sink for air cooling set ups or extensive radiator mounting possibilities for water cooling setups

  • Extensive water cooling support for a case of this size; housing radiators up to 420 mm in the top and 360 mm in the front

  • Including smart reservoir brackets; featuring drill-free reservoir mounting on the front of the motherboard tray and pre-drilled pump mounting holes on the bottom panel

  • Including two Fractal Design Dynamic GP-14 140 mm fans developed for superlative airflow and low noise levels

  • Equipped with ModuVent™ fan slot covers providing the option of additional cooling or maximum sound absorption

Smart open layout and storage functionality

  • Maintaining a dust-free interior with dust filters that cover the front and bottom air intakes

  • An additional two dedicated steel SSD trays cleanly placed behind the motherboard tray

  • Long motherboard tray extending to the front panel contributing to an extremely clean build, hiding both hard drives and cables

  • Introducing newly designed hard drive trays placed vertically behind the front partition of the motherboard tray; Three sturdy steel trays with vibration-dampening grommets allowing for installation of one 3.5" or 2.5" drive on each tray, without disrupting the airflow or interfering with the radiator mounting possibilities


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"Fractal Desing have really made something special here. From the exterior, it’s as stylish and bold as any other Fractal Design chassis, but the interior is a breath of fresh air. If your next build is going to feature high-end water cooling, this is the perfect chassis for the job."
"Anyone looking for epic cooling should buy this case."
"The Define S is solid and attractive enough to hold an “Ultimate Liquid Cooling” build."


  • 3.5" HDD/2.5" SSD positions
  • 2.5" dedicated SSD unit positions
    2 (fits SSDs up to 17 mm thick)
  • Expansion slots
  • Front ports
    2x USB 3.0, Audio in/out, Power button with LED (blue), HDD activity LED (blue), Reset button
  • Total fan mounts
  • Front fan
    3x 120/140 mm (included 1x Fractal Design Dynamic GP-14 fan @ 1000 RPM)
  • Top fan
    3x 120/140 mm or 1x 180 mm with 165 mm hole spacing
  • Rear fan
    1x 120/140 mm (included 1x Fractal Design Dynamic GP-14 fan @ 1000 RPM)
  • Bottom fan
    1x 120/140 mm
  • Dust filters
    Front fans, Bottom fans
  • Cable routing grommets
  • Fixed velcro straps
  • Captive thumbscrews
    Both side panels
  • Left side panel
    Clear transparent window
  • Right side panel
    Industrial sound-dampened steel


  • Power supply type
  • Motherboard compatibility
    ATX, Micro ATX, Mini ITX
  • Front radiator
    360, 280, 240, 140 or 120 mm
  • Top radiator
    420, 360, 280, 240, 140 or 120 mm (a thickness limitation of 55 mm for both radiator + fan applies on 420, 280 and 140 mm radiators)
  • Rear radiator
    120/140 mm
  • Bottom radiator
    120 mm radiator (Use of radiators in the bottom position limits the PSU length to 165 mm)
  • PSU max length
    180/170 mm with a bottom 120/140 mm fan installed or 300 mm when not using any bottom fan
  • GPU max length
    425 mm with front fans installed, without compromising HDD capacity or 450 mm without front fans installed directly in line with the GPU
  • CPU cooler max height
    180 mm
  • Cable routing space
    20-40 mm


  • Case dimensions (WxHxD)
    233 x 451 x 520 mm
  • Case dimensions - with feet/screws/protrusions
    233 x 465 x 533 mm
  • Net weight
    8.5 kg
  • Package dimensions (WxHxD)
    322 x 615 x 535 mm
  • Package weight
    10.2 kg


  • Warranty
    2 Years
  • Package contents
    Define S computer case, User manual, Accessory box
  • EAN
  • UPC
  • Product code
  • Additional information
    Available for System Integrators