Product	MTBF
Telestra 4	47,185.77 hours
T4 Hard Drive	250,000 hours
ACE-RIU	251,042.45 hours (COTS) 119,713.60 Hours (Mil Spec)
ACU	246,493.02 hours (COTS) 122,999.41 hours (Mil Spec)
ACU2	108,100.75 hours (COTS) 48,390.23 hours (Mil Spec)

It is important to realize that as different ACENet devices support different features the MTBF numbers between those devices will vary. The ACE-RIU for example supports 4 Mono Audio Outputs, while the ACU2 supports 4 Stereo Audio Outputs. So with a stereo operator requirement you can put 4 operators on an ACU2, but only 2 on an ACE-RIU. Additionally the ACU2 has more IO capability, software gain control, etc.