... Type:spray metal/ T, Full size/ Slim Hole 4)SM Coating Material:Ni60A Alloy Coating 5)Coat Thickness: ... 595HV0.2 11)Coupling diameter: 5/8"to3/4 ",3/4"to7/8". 7/8"to1", 1"to1-1/8" 12 ... )Main specification of 3/4"to7/8"sub ... them are available in sizes of 5/8",3/4",7/8",1",1-1/8" If you are ... best service all the time. API 3/4" *7/8" Sub Sucker Rod Couplings,Class SM