McAlpine 40K-CB chrome plated blanking cap in 40mm size used to blank off chrome compression tee (42E-CB). The purpose of a blanking cap is to seal off one end of a fitting, preventing the flow of fluids or gases through that particular branch of the pipe. In the case of the McAlpine 40K-CB, it is used to seal off the end of the compression tee where a pipe or other fitting would typically be attached. Blanking cap is equipped with additional gasket for better seal.