Application Gas Struts 2pcs 1pair are used for such as RV bed, Rv Door, Cabinet Lid, Box Lid ,Outdoor TV Cabinet, Rv Bed, Truck Canopy, Trap Door, Trash Bin, and other Custom Project, Different sizes apply to different scenarios, clear demand parameters before purchase Detail Parameters Extended Length 13.00 inch, Compressed Length 8.28 inch, Force 55 Lb245 N, applicable lid weight range 44 60.5 Lb , For use between 20 26 inch; Silver onepiece steel head thread ID 6 mm, bolt diameter 8 mm, nut ID 8 mm, 1 x Installation Instructio Easy to Install Package includes Springs x 2, thickened L bracket x 4, M8 nut x 4, installation instruction x 1. Follow the instructions to choose the mounting point and install it. Also, installation reference videos are available everywhere on the internet Tips If you feel it is too powerful to close and you have a lot of flexibility in where they can mount, you can move the mount point on the lid towards the hinges direction 121 Month Replacement Welcome to Click Ask Seller Beside Your Order for Intime Assistance if any problem occurs