Sealey calibrated micrometer torque wrenches sealey premier stw103 this micrometer style torque wrench from sealey has a chrome vanadium steel ratchet head with smooth action mechanism each wrench is individually tested to standards with plusmn4 accuracy and each wrench is issued with an individually numbered test certificate sealey stw103 torque wrench micrometer style 34sq drive 70 420nm52 310lbft