The NDS Pro-Spec 17" x 30" body is tapered and has a minimum wall
thickness of 0.320". The body has a double wall at the top cover seat area with a
minimum thickness of 0.320". The cover seat area has 20 structural support ribs on
the underside of the seat, each with a minimum thickness of 0.250". The bottom of the
body has a 1.000" flange. The 17" x 30" cover has an average thickness of 0.350".
The valve box shall have a 3/8" 304 S5 nut for the bolt-down as a standard feature.