The popularity of 5mm battery plugs can sometimes cause a challenge when using different battery packs with differing plug sizes during the same track day. Tuning Haus provides a safe solution to your charging needs with premium dual-sized bullet connectors containing a center port for easy assembly and soldering. In addition, rubber safety caps are supplied to protect the unused sides from potential safety hazards. Package contains 2 each 4/5mm bullet connector, 4mm rubber cap and 5mm rubber cap.