Custom Return air plenum, for filter grill 20 x 30" and 18" collar.

This is a custom
Return air, plenum,for filter grill  30-1/8 x 20-1/8 x 5″ .
Made in America
by hand from American made 26 Gauge Steel Galvanized Sheet Metal . There is a
3/4″  flange on one 30″x20″ end
Outside the plenum (around the flange) has dimensions 31-5/8 x 21-5/8″ and height 5″
, and the other side is fitted with an end cap with a 18″ diameter  collar.
From top to bottom the plenum is 5″
long and the collar measures 4″ in length.
Custom production no return.