Step-Down Butt Connectors have a varied diameter of terminal barrel to give a positive crimp on each different gauge wire end. Blue band denotes 16-14 AWG and Yellow Band denotes 12-10 AWG. Strip wires and insert into appropriate end of connector and firmly crimp. Internal wire stop prevents over insertion and translucent insulation allows for a visual inspection. Slowly apply heat (275degF) until inner adhesive wall of sleeve softens, melts filling voids, and outer wall shrinks. Cool for a waterproof and corrosion resistant connection.