RS Pro Insulated Crimp Blade Terminals. An RS Pro series of insulated crimp blade terminals made from copper with flared vinyl insulation. These insulated crimp blade wire connectors are colour coded for use with different wire sizes. All models are highly reliable and excellent quality. Features ; Benefits. Red 0.5 - 1.5 mm² Blue 1.5 - 2.5 mm² Yellow 2.5 - 6.5 mm²