The TB is a small torque wrench with a fixed head. The versatile preset wrench is available with different head configuration options, like open end, box end, flare end, hex key end or ratchet head,(THIS IS THE RATCHET HEAD MODEL).. TB models are designed to have one permanent head style attached to it. When the TB torque wrench achieves torque, the head breaks-over signaling to the operator to stop applying torque to the fastener or bolt. Break-over torque wrenches improve control of the fastening process by reducing the risk of both over and under tightening.