A must have for boat trailers: trailer bunk slides pads definitely launching and loading boat on and off trailer quickly with minimal effort.Makes loading and unloading on/off the ramp much easier! Fit for almost any bunk trailer,includes 2Inch, 4Inch 6Inch boat trailer bunk slides.Boat weight limitation: 1,500 lbs for fiberglass boats, 4,000 lbs for metal boats. Works on bunk trailers for unpainted bottom boat pontoon boat/jon boats/jet ski//waverunner/fishing boats. It's not recommened for painted bottom boat,because may scratch the bottom paint. Our boat trailer slides for bunk are with recessed screw holes for a firm mount. Just be make sure the screws drop into countersink area to prevent scratching hull. Don't release from the trailer hookup until backed into the water.Just remember unhook boat before taking boat out of water.Because trailer slides for bunks are very slick and your boat slide off on a steep boat launch. More warm tips pls see below information and instruction. Note: Installation guide not included, we strongly recommend you professional installation. Please check as much as possible to make sure the item is what you need. Tips:The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use. Color:Black Material:ABS Package Contents: 8 * Pads (3x10Inch) 2 * Bunk Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.