This is a stacking retractable sleeve plug output cable kit. Added safety and protection when standard jack connections are encountered. Clear covering sleeve retracts as you plug into the jack. Banana plug includes a red plastic insulation tip for added protection. Materials: body: polyamide (nylon); contact: brass, nickel plated. Banana contact: BeCu, nickel plated. Kit contains a red, green and black cable of 150cm length.