The Keystone is an excellent option for a high-traffic area with the lowest cost-per-visitor of our standard models. The all-user restroom cabin provides valuable versatility helping cut down the lines on the men’s or women’s sides should there be an imbalance in demand. The all-user cabin also provides more privacy for visitors that need it, such as young families and people with caretakers. The Keystone can operate with flush toilets and sinks even without any connection to utilities such as sewer, water, and power.