Ancor Marine Grade Products 12-10 AWG Heat Shrink Step-Down Multi-Wire Connectors (3 Pack) 4:1 shrink ratio tubing to ensure a watertight seal between wires Flared barrel with uniform Copper wall ensures an easy and proper mechanical crimp Crimp indicator on barrel for proper placement of installation tool Clear heat shrink tubing ensures crimp accuracy Colored stripes on the barrel indicate which crimp die to Use, regardless of application