The Model 306L Type A Durometer is designed to measure Natural Rubber, Elastomers, Fluoroelastomer, Neoprene, Silicone, EPDM, Buna-N, Latex, ECH, Polyethylene, Polyurethane, Viton, Santoprene, SBR, Vinyl, Butyl, Soft Plastics, Felt and Leather. PTC's Model 306L meets or exceeds current ASTM D2240 Specifications. Accurate readings can be obtained in any position. The instrument has a low glare aluminum dial with bold, easy to read numbers. The durometer comes standard with a Max Hold hand which retains the OK reading. A top knob with 8-32 threads permits both easy hand held use and attachment to test stands