Traxxas Velineon VXL-4S Brushless Electronic Speed Control. This ESC is a replacement for the Traxxas Maxx Monster Truck. 

Specifications

• Input Voltage: 3S–4S LiPo (11.1V – 16.8V)
• Case Size: 2.83 inches (72mm) x 2.32 inches (59mm) x 1.93 inches (49mm)
• Weight: 201g (7.09oz)
• BEC Voltage: 6.0 V
• BEC Current Continuous: 10 A
• BEC Current Peak: 20 A
• Motor Connectors: Traxxas 6.5mm bullet connectors
• Battery Connectors: Traxxas High-Current Connectors
• Power Wire: 10-gauge Maxx Cable
• Ports: RX input, auxiliary fan, Traxxas accessory port