Package:You will receive 2 x Pool Winter Cap. The large has a diameter of 51mm and the small has a diameter of 38mm. It is tapered in shape and has great adaptability, which can meet your usage needs. High Quality Materials:Pool Winterizing Plug is made of high quality rubber with good sealing. The bolt is made of stainless steel, corrosion resistant, not easy to rust. Protect the swimming pool:The Swimming Pool Winterizing Plug ensures the safety of swimming pool pipes by clogging the pipes to prevent water to get in and freeze. Easy to use:The pool plug has a scientifically sound design with two keys that make it easy to install and remove. Wide range of 'applications:Swimming pool winter plugs can be used not only as pipe plugs to prevent winter water from entering the pipe. It can also be used during leak detection or pressure testing to stop pool water flow during maintenance.