Seidon 120M

Disclaimer: Displayed parts and accessories may not be included in the actual product package.

The Seidon 120M is Cooler Master’s latest, incredibly compact watercooling kit that aims to bring watercooling to the masses. It fits in virtually every case, is compatible with every available Intel and AMD platform, and as easy to install as a heatsink. It comes factory filled, sealed and tested with a two year zero maintenance guarantee. Thanks to a 120mm PWM fan with a wide RPM range Seidon can operate silently or unleash a powerful cooling storm at your command.

  • Factory filled with coolant, then sealed and pressure tested - requires zero maintenance for years.
  • Compact and durable all in one waterblock secured with 12 stainless steel bolts.
  • Waterblock machined out of a single block of copper for the best possible heat transfer.
  • Precision machined Micro Channels maximize the water contact surface to quickly dissipate heat.
  • Compact 120mm aluminum radiator fits in virtually any case, internal or external.
  • Fin design optimized for minimum air restriction to reduce fan speed and noise.
  • 120mm PWM fan with a wide RPM range to fine tune and balance fan noise and performance.


Model RL-S12M-24PK-R1
CPU Socket Intel LGA 2011 / 1366 / 1156 / 1155 / 1150 / 775

AMD Socket FM1 / AM3+ / AM3 / AM2
Main System Dimension Ø 70 x 27mm (Ø 2.75 x 1.1 inch)
Radiator Dimensions 150.3 x 118 x 27mm (5.9 x 4.6 x 1.1 inch)
Radiator Material Aluminum
Fan Dimension 120 x 120 x 25 mm (4.7 x 4.7 x 1 in)
Fan Speed 600~2400 RPM (PWM) ± 10%
Fan Airflow 19.17 ~ 86.15 CFM ± 10%
Fan Air Pressure 0.31 ~ 4.16 mm H2O ± 10%
Fan Life Expectancy 40,000 hours
Fan Noise Level (dB-A) 19 ~ 40 dBA
Fan Bearing Type Rifle bearing
Fan Connector 4-Pin
Fan Rated Voltage 12 VDC
Fan Rated Current 0.3A
Fan Power Consumption 3.6W
Pump Life Expectancy 70,000 hrs
Pump Noise Level 17dBA
Pump Connector 3-Pin
Pump Rated Voltage 12 VDC
Pump Load Current 0.15A
Pump Power Consumption 1.8W
Warranty 2 years
UPC Code 884102018930
  • +
    • Click logo to read full review:  Bronze : June 2013

      "The Cooler Master Seidon 120M is an entry-level liquid cooling system, easy to install and fits virtually any case.  It equals the performance of the high-end air coolers, and the price tag is also comparable."

      » Details 8 / 10 : January 2013

      "What we thought was a great design was the maintenance free operation.  You would not have to play around with Seidon 120M to get water levels adjusted or replace water when there is a problem.  This unit is pretty much a Set it and Forget it one stop water-cooling solution.  Seidon 120M retails for about 70$ at the time of the review and is very well priced according to its performance."

      » Details  Highly Recommended : December 2012


      The Cooler Master Seidon 120M is a great little closed-loop cooler that would be ideal for those looking to replace an OEM or low performing coolers. The performance of the Seidon cannot be touched by anything in the OEM realm making it worth the investment is looking for a better cooling situation and some that can grow with you are you moved through different platforms.

      The Seidon 120M is in the same league as the Thermaltake Water2.0 Performer and the Corsair H55 and H60 as far as performance goes. But it one up the Thermaltake model and the Corsair H55 due to its mounting hardware, it is so much easier to prepare and mount to the motherboard. And it also one up the H55 due to a better performing fans."

      » Details Silver Key Award : November 2012

      "The Seidon was not the best all-in-one we have ever tested; it was not even the second best. However it is the best all-in-one we have tested at the price point it is at. We have yet to see a cooling system like this for under $80 that can maintain decent performance when pushing an overclocked top-end CPU. We were pleasantly surprised to see the temps that we did from the Seidon. We do think that Cooler Master has some room for improvement; they could have added a copper radiator to increase the thermal dissipation and also included better thermal interface material for use in mounting this on your CPU. Perhaps in future models Cooler Master will add in liquid metal and a copper radiator as an “enthusiast” option. If they did the Seidon would be one amazing product. As it stands we are still able to recommend it to any of you that are interested in adding water cooling into your rig, but do not want to build it piece by piece. In fact the Seidon is good enough to earn our Silver Key award for its build quality, price and performance."

      » Details  Great Hardware : November 2012

      "Cooler Master has developed a great AIO CPU Cooler without breaking the bank that can provide excellent thermal performance along with lasting appeal. "

      » Details

  • +
  • +
  • +
    • Online Stores:

      Distributors & Others:
      No location available.

  • +