... sizes of down-hole motors for the sizes through 3-1/2"~17-1/2". Popular sizes are 2-7/8", 3 ... -1/8", 3-1/2", 3-3/4", 4", 4-3/4", 6-1/2", 6-3/4 ... ", 7-3/4", 8", 8-1/2" and 9-5/8". We can supply down-hole ... /8"~9-7/8"9-7/8"~12-1/4"OD, inch4-3/4"6-1/2"6-3/4"7-3/4 ... end connecting thread3-1/2" IF4-1/2" IF4-1/2" IF6-5/8" IFBit connecting thread3-1/2" REG4-1/2" REG4-1/2" REG6 ...