These blue collet clips are placed on plastic plumbing pipes in order to indicate that the water inside the pipe is cold.
FloPlast Flofit+ Push Fit Chrome ISO Valve - 15mm x 15mm
FloPlast Flofit+ Push Fit Reducing Tee - 15mm x 15mm x 22mm - Pack of 5
FloPlast Flofit+ Push Fit Reducing Tee - 15mm x 10mm x 10mm - Pack of 5
FloPlast Flofit+ Push Fit Pipe Insert - 22mm
FloPlast Push Fit Collet Clip Blue Cold Water Pack of 50 - 22mm - FloFit+
FloPlast Push Fit Collet Clip Blue Cold Water Pack of 50 - 15mm - FloFit+