Scythe S-FLEX SFF21E / 120mm 1,200rpm Fan. Scythe S-Flex Computer Case Fan SFF21E Air volume at full speed (12V) CFM 10%: 49.0 Noise level at full speed (12V) dB(A): 20.1 Life expectancy @ 25C: continuous use 17 years Rated voltage: 12 VDC.