A Torque Meter with Blast tube protects the fuselage from blown motors, while providing an accurate measurement of the "power" wound in your rubber motor. Trimming a rubber powered model is simplified with a Torque Meter by allowing you to accurately duplicate the "power setting" flight after flight regardless of the number of winds or weather conditions. The BMJR P-30 Torque Meter is calibrated between 0 and 12 in-oz , is 23” long and includes a 20” blast tube. Perfect size for use with P-30 class rubber powered models. However we have used this meter on larger motors, exceeding 12 in-oz with out damage.