Another issue with using a HANS is that the teathers have an expiration date(2 years). So if the SFI 2 year belt/window-net date burns your derryair, be warned. The flip side is that some organizations expect all the other types (Defender/R3/ect) to have expiration dates on their teathers like the HANS, which they don't. Dates on the teather isn't even part of the certification for 38.1, but HANS decided to put it on all the same.