Used at both ends of the brake line tube and the transmission line tube, it is very useful. Oh, the inner diameter of the plastic brake line cap is 5mm, and the inner diameter of the transmission is 4MM 

Variable speed line cap brake line cap

[specification] 4mm(variable speed)   5mm (brake)

[color] black metallic

Variable speed line pipe cap: plastic    Brake cap: copper

Variable speed line pipe cap:

Brake pipe copper cap: