the Sensor Board and Sensor is used for measuring motor/engine RPM's

Molded in clear

and the battery just by inserting the battery into the slot

The innovative capacitor overheat protection function can avoid a capacitor explosion caused by overload and damage the ESC

Traxxas 5070 Top Fuel 20% Gallon Rock Crawlers the Sensor Board and SensorTraxxas Top Fuel, 20% nitro content, one gallon. 20% is the standard blend for most nitro running enough nitro for strong power and easy tuning without the heat and shortened engine life that come with higher concentrations. Traxxas Top Fuel carries a heavy lubricant package, which is what protects the piston and sleeve during break in and hard running. The gallon is the economical size if you run regularly. Keep it sealed between sessions, since