Services: Portable Toilets - Ranging from basic to extra-large units. We also provide specialized facilities for wheelchair access as well as baby-changing units. Holding Tanks - A holding tank, also called waste water holding tank or black tank, is a container for storing sewage in vehicles equipped with toilets. Vehicles that use holding tanks include recreational vehicles, trucks or boats. A/C Restrooms - A/C Restrooms, also know as restroom trailers, are a lot different then traditional portable toilets. There are private stalls, real flushing toilets, and sinks in vanities with mirrors and lights. Shower Trailers These trailers are very similar to the restroom trailers except they also have showers, giving the users the feeling of a home bathroom but on the go.