Protects Against Costly Propeller Theft In And Out Of The Water; Fits Stern Drives And Outboard Motors: MerCruiser Alpha I/ Bravo I (With X And XR)/ TRS/ Vazer/ OMC Cobra and King Cobra/ Mercury/ Mariner 70 HP And Larger (2 Stroke)/ Mercury 40 HP And Larger (4 Stroke); Optimax 75 HP And Larger/ Verado 135 HP And Larger/ Johnson/ Evinrude 150 HP And Larger (2 Stroke); 3/4 Inch x 16 Thread Size; 1.025 Inch Overall Length; 1-1/16 Inch Hex Size; Naval Brass And Stainless Steel; Includes 1 Lock And 1 Key