The unit is made via injection mold which allows us to manufacture a seam free product.  All threaded fittings on the tank are molded into the tank and supported via bosses and ribs which allow for an extremely durable tank.  The tank is so strong it can withstand being dropped 15 feet onto concrete, hit with an 8 pound sledge hammer, and driven over with  a 10,000 pound truck.  We are working on a video as we speak demonstrating the robustness of the tank which will provided on the website shortly.