Two types of coupling are available: Class T and Class SM, full size and ... 11B Two types of coupling are available: Class T and Class SM(spray metal rod coupling), full size and ... of sizes. The minimum tensile strength of the coupling is 95,000 psi (655MPa) and the ... to 62 HRAWe also provide Sub-coupling: 5/8-3/4 T(SM), 3/4-7/8T(SM ... ), 7/8-1T(SM), 1-1 1/8 T(SM). sucker rod coupling ...