Traxxas Servo Digital High-Speed Metal Gear (Ball Bearing) Waterproof Slash 4X4 Optima Parts Protects the throttle servo from

Protects the throttle servo from shock loads

Current Drain for Balance Ports: 500mA

Confirm that the battery will physically fit your model and that the electronic speed control supports the selected 4S voltage

80C continuous discharge rate

This is the Altimeter from Estes

Traxxas Servo Digital High-Speed Metal Gear (Ball Bearing) Waterproof Slash 4X4 Optima Parts Protects the throttle servo fromTraxxas Servo Digital High Speed Metal Gear (Ball Bearing) Waterproof Slash 4X4 Fits: Slash 4X4 Ultimate Unlimited Desert Racer E Revo VXL Brushless Rustler 4X4 VXL TRX 4 Assembly Kit TRX 4 Ford Bronco TRX 4 Scale and Trail Crawler TRX 4 Sport TRX 4 Tactical Unit