They've been around for many years and quite a few 100 have been sold at least. Good lil'ol'trommel and the oscilating sluice is a hoot to watch as most folks are not familiar with the concept but when properly applied it works great,wrong a nightmare. They used to be trailer mounted,just unhook,prime the pump and away ya go. Properly run at least a yard a hour with a mini bakhoe/mini bob or 3 fellas-John