Schmitt & Ongaro Marine Throttle Knob - 1-1/2" - Red Grooves. 1-1/2" Throttle Knob - Red Grooves 316 Cast Stainless Steel 1-1/2" Throttle Control Knobs Fit Morse MY-3 MV-2 Twin and Single Controls with 3/8" -24 Threads Throttle Knobs are colored for Sight and Grooved for Feel - Meets ABYC Package Contents: Schmitt & Ongaro Marine Throttle Knob Schmitt & Ongaro Marine 50020: Throttle Knob - 1-1/2" - Red Grooves