Thread Check Inc offers sucker rod thread gages  per API spec 11B The designations are listed below For sucker rod pin connections Go pin thread ring gage = P8 No Go pin thread ring gage = P6 Pin cone ring gage is P4 which is used on polished rods only Go pin P2 ring gage is used on polished rods and does not check 9 degree cone For sucker rod box connections The go box thread plug gage B2 does not check 9 degree cone on polished rod couplings and sub couplings. Box cone plug gage B4 is used on polished rod couplings and sub couplings. Do not use on sucker rod couplings. No go B6 is used on sucker rod couplings and sub couplings The product pin should not enter the P6 ring gage more than 3 turns. The product pin should enter the P8 ring gage to shoulder face pin contact A .002" feeler gage should not enter between the face of the gage and the pin shoulder face. For more information and pricing on sucker rod plug and ring gages contact Thread Check Inc   800 767 7633 [email protected]