With rotomolding technology, TOPPLA toilets are better than injection toilets in quality. The water tank is 160L and the waste tank is 280L, the biggest ones in the world. Very easy to install, only screw drivers and wrenches are needed. One unit can be finished within 30 minutes by 2 people, installation instructions and video are also provided. Special design enables the toilet to be moved by forklift and crane directly. Equipped with steel skit, the toilet is popular in construction sites. http://www.topplatoilet.com/tpt-h03-building-site-toilet-construction-porta-potty.html