Compatible with Spider, Eagle, X2, X, Ultra 2, Ultra, Dualtron 3, Compact, Mini, Raptor 2, Storm NEW, Ultra 2 Upgrade, Thunder 2, Spider 2, Victor, Victor Luxury, X2 UP, and Achilleus. This 4-pin charging cap is part of the electric system and charging port protection setup. Compact replacement cap for covering and protecting the charging connection.