The BEST Seal Kits Available for Auto Transporters , only available from the Oil field Technology , of Alberta , Canada this one is designed for the top end of your cylinder for Cottrell trailers Only , Size of this Kit is 1.50" rod x 2.50" bore ( inside diameter ) the large cylinder used on Cottrell Trailers , easy to install , , these are made from Nitrile Synthetic Rubber , which keeps these seal kits flexible under EXTREME cold weather , and Guarantees you a solid leak proof seal for many Years , feel free to reach out with message with any questions , Thanking you for your Purchase , Keith Andes former Owner Operator , bringing you quality products over and above factory OEM standards , UPGRADE TODAY , with my PRODUCTS !!!!!!!!