The Protec20 is a high quality 12 gauge steel tank with an outer shell of polyurethane.  To demonstrate the superior level of protection provided by the Protec20 we drilled three 0.25" inch holes in the primary 12 gauge tank prior to applying the polyurethane coating.  Once the drilled  20+ tank had been trough the complete manufacturing process, we sealed it and pressurized it to 25 psi.

As this video demonstrates, at 25 psi the tank swells and distorts from its original shape yet despite the three 0.25" drilled holes, IT DOES NOT LEAK. 

The Protec20 is an exceptional tank.