After a little google search I found the different branded HANS devices. Each vendor seem to have added their own improvements and it looks as the base is the same with the exception of the Schroth. I thought it was interesting enough to share on the forum as the HANS device is now required for many of us. (See pictures below)
The HANS Device (not branded) and with the optional sliding tether:

The HANS Device Engineered by Stand21 with air padding and anchors:

The HANS Device Engineered by OMP:

HANS Device Engineered by Schroth:
