Add a screw, nut and washers for $6.00 more, use the menu to select and see available stock levels for each option. This part secures the base of the Tarpon CSS seat back assembly found on Wilderness Systems Tarpon, and the Perception Pescadore, both circa 2002-2009 as well as the Pompano (West Marine) circa 2012 to date. Also for Perception Search and some Wilderness Systems Ride sit-on-top kayaks. Might work on Future Beach kayaks too. If you are replacing a damaged seat clip you can re-use the original mounting hardware. If you are installing a new seat back assembly you will need the seat clip with the hardware pack. Super Easy to install! Drill one hole for the seat clip screw. The rubber back washer (goes inside) seals against water. Slip on regular washer (inside). Tighten the nut with a wrench through open rear hatch. Clip is 1 x 2.25 inches, just over one inch high. The diameter of the semi-circle opening is 7/8 of an inch. (Alt part number 5020-8001) Come with one each; 1 Nut 9800259, Screw 9800298, Washer 9800348 and Neo-Back Washer 9800257. CSSOUT