US Series roto molded racks are 19” deep racks with a molded-in unbendable valance, steel threaded rails, self tapping screwsSKB catalog page (PDF): US Series Racks iSheet
ATA Rated ATA (Air Transport Association) specification 300, category 1 is the highest standard for an airline transport container (a minimum of 100 common carrier trips). Category II has a minimum of 10 trips by air.