Cooler Master's new Seidon 120XL liquid CPU cooler is a higher-end version of its original 120M cooler. Beyond having an extra added fan, the radiator is also a tad thicker. The original 120M had a radiator with a 27mm thickness, while the new 120XL has a radiator that's 38mm thick. The CPU block hasn't changed; it is still made of copper and has a 1.8 watt pump that has a MTBF (Mean Time Between Failure) of 40,000 hours.
The Seidon 240M is the bigger version of the 120M, with a radiator that is 240mm long rather than 120mm. The radiator's thickness remains the same, at 27mm, and is only meant to house the fans on one side, not both. The CPU block has a similar copper base as the 120XL, but has a more durable pump with a rated MTBF of 70,000 hours.
The fans that come with both units are identical. The 120mm fans spin at speeds from just 600 rpm all the way up to 2400 rpm. This gives these units the potential to be very silent, or very loud when they need to deliver some proper cooling power. Both the coolers are compatible with almost all modern CPU sockets, amongst which Intel LGA 1155, LGA 1156, LGA 1366, LGA 2011, along with AMD's AM2, AM3, AM3+, FM1 and FM2 sockets.
The Seidon 240M has already been listed on Newegg for $94.99.