SCHMITT ONGARO MARINE PRODUCTS ONGARO THROTTLE KNOB RED 1.5 GROOVED 500201-1/2 Throttle Knob - Red Grooves316 Cast Stainless Steel1-1/2 Throttle Control Knobs Fit Morse MY-3, MV-2, Twin and Single Controls with 3/8 -24 ThreadsThrottle Knobs are colored for Sight and Grooved for Feel - Meets ABYC Specifications