Skip, it's the 57mm one, unsure of manufacturer though.
age, 14 years according to the maintenance logs - ie it's the original one fitted.
I check it as part of my pre-flight routine during taxi and line up.
Only used it once during flight to verify that the Aspen PFD was having a bad day, once. It confirmed that the Aspen was telling me lies.
But I also have an Ipad, a Garmin 296 and my mobile in the plane, so plenty of redundancy.