The Usage Calc app from Satellite Suites works with Satellite Suite restroom trailers to help determine the right-size trailer to place on site. It is available in both the Apple and Google Play stores under the name Usage Calc. The app provides information on trailer sizes 6 by 10, 6 by 14, 8 by 20 and 6 by 10 International with the allowable number of uses based on the trailer tank size. To use, open the app, choose trailer size, and use the slide bar and buttons to determine the maximum number of uses. 574/350-2150; www.satelliterestroomtrailers.com.