These blue collet clips are placed on plastic plumbing pipes in order to indicate that the water inside the pipe is cold.
FloPlast Push Fit Waste Bend - 135 Degree x 32mm Black
FloPlast Push Fit Waste Bend Swept - 92.5 Degree x 40mm Grey
FloPlast Push Fit Waste Bend Swivel - 90 Degree x 32mm Grey
FloPlast Push Fit Waste Tee - 40mm Grey
FloPlast Push Fit Waste Socket Plug - 40mm Black
FloPlast Push Fit Waste Bend Swept - 92.5 Degree x 40mm Black