Cottrell Trailer Hydraulic Cyl. Gland Nut 2” Seal Kit # 12319-G , Packing Nut . These Wiper Seals are a upgrade made with Nitrate synthetic rubber , more flexible , holds up in extreme cold weather conditions , the only seal kits used in the Canadian oil fields on all there hydraulic cylinders are Nitrate Seal Kits , now available in the Auto Transport industry , cost , value , benefit , these seals outlast all other seal kits on the market , once you’ve used these Nitrate synthetic rubber seals , you will always be a fan , thanking you for all your business , sincerely All The Best , Keith A.