These red collet clips are placed on plastic plumbing pipes in order to indicate that the water inside the pipe is hot.
FloPlast Flofit+ Push Fit Stopend - 22mm
FloPlast Flofit+ Push Fit Coupling - 15mm
FloPlast Flofit+ Push Fit Collet Clip Blue Cold Water - 15mm - Pack of 10
FloPlast Flofit+ Push Fit Coupling - 15mm - Pack of 10
FloPlast Flofit+ Push Fit Reducing Coupling - 22mm x 15mm
FloPlast Flofit+ Push Fit Reducing Tee - 15mm x 10mm x 10mm - Pack of 5