Belmor VS-MT3-1 Stainless Steel Ventshade for 1974-2004 Mack DM600, DM600S, DM600SX, DM600X, R, RB600S, RB600SX, RD600, U600, U602, R Series (Dummy Shutter) Lets fresh air in, keeps rain, snow, stale air, odors, and heat out  while keeping the elements at bay and reducing interior fogging Helps keep the driver comfortable and alert Stainless steel bright finish Customized to fit most classic truck makes and models including those with larger cab doors Made in USA and backed by a Limited Lifetime Warranty