This is a resin detail parts set for use with military vehicle kits.
Lion Roar makes some of the best photo-etched metal and resin detail sets around, and here's another beauty! Limited to only 600 sets worldwide, this 1/35 Staghound AA armored car set features resin stowage parts, turned brass twin .50 cal. machine guns, and more! Designed for the Bronco kit (linked below).