This is Du-Bro's 1/4"-28 Aluminum Spinner Prop Nut. FEATURES: Plain silver aluminum spinner. Meets AMA safety specs. CNC machined from 6061 T6 aluminum. Works with standard electric starting cones. This will fit the following engine models: ASP- .21 ABC-.46 ABC ENYA- SS.25, SS.25BB, SS.30, SS.30BB, .35X, SS.40, SS.40BB, .46 4S, SS.45Ring, .41 4S Fox- .19RC & CL, .25RC & CL, .35CL, .40RC & CL, .50RC BB, .45RC Schnuerle, .40 Quickie Fitzpatrick- .61 ABC HB- .20-.61 all models HP- .21-.61 all models Irvine- .20-.61 all models K&B- .20-.65 all models Magnum- GP.25, GP.40, Pro.25, Pro.36 SE, Pro.40 SE, Pro.46SE MDS- .46, .25-.40 Merco- .33-.40 Moki- .61 Long Stroke all models O.S.- .20-.50 all models, .61SFN-H RC, .61RFN-H ABC, FS.26 Surpass, FS.48 Surpass, FS.20, FS.40 Picco- .21-.45 all models Royal- .25 & .28 RC BB ABC, .40 RC ABC Schnuerle, .45 RC BB Schnuerle ABC, .46 RC BB Schnuerle ABC Supertigre- .19-.56 all models, .60G & ST Thunder Tiger- GP.25, GP.42, Pro.25, Pro.46, F-54S Webra- .21-.60 all models INCLUDES: (1) Aluminum Prop Nut SPECS: Approx. Weight: 1oz Shaft Size: 1/4"-28 COMMENTS: Tighten nut with a screwdriver, ball driver or steel rod. 08-20-98kzh ir/jl kr3/17/03 BOX DIMENSIONS: 3.00" W. X 1.25" H. X 6.50" L. BOX WEIGHT: .07 LBS.