Line air supplied at 85 psi holds Model PFS47 open; springs clamp it shut when pressure is removed. Brake exerts max tangential force of 465 lb at full pad wear, which translates to 3,310 lb-in. torque on 16 in. disc. Replaceable non-asbestos pads distribute friction across 4 in.2 contact surface. Available models fit discs 5/32, 1/4, 3/8, and 1/2 in. thick.