Square Wheel Industries has introduced a faster, more efficient method of testing the trailer light and air brake system that can easily be fit to mobile service trucks. Whether it is a step van or a tow truck, the Express Mobile™ can keep your investment as productive as possible. With the Express Mobile™, all lighting functions and the air brake system (including brake adjustment) can easily be checked in just two minutes, start to finish. An isolation valve on the unit allows leak down tests on individual air valves. For a service center, this can translate into inspection of 20 trailers per hour... including set-up, disconnect and all walk time.