Test couplings with ball valve (SMK) and poppet valve (SKK) and accessories from the STAUFF Test 20 series with connection thread M16x1 according to ISO 15171-2 with 37° JIC connection according to SAE J 514. Available in steel with zinc/nickel coating or in V2A and V4A stainless steel. Maximum operating pressure of 630 bar. Coupling under pressure up to 400 bar. Self-locking knurled cap made of metal. Optionally with hexagonal cap made of metal or plastic cap.