The Rex OS-4H-E Durometer Test Stand for OO Scale AD-100 and DD-100 Durometers is designed for use with our type OO & OOO durometers. The stand, used in conjunction with our Durometers increases repeatability while eliminating operator error.The stand features a load weight for the proper testing pressure as noted in ASTM D2240, and a quick-lock column for easy adjustment.