Bando 600-S4.5M-450 S4.5M-450 Timing BeltBando 600 S4. 5M 450 Unique modified curvilinear tooth form enables the STS belt to transmit greater loads than like sized drives having the standard high torque tooth profile. Smoother tooth engagement and direct contact of belt tooth top with the pulley grooves enables the belt to run quietly even at high speeds. As the tooth meshes with the pulley grooves, the cord lay forms an almost true circle, minimizing the cantilever effect on the cords,