Viking QR COIN® Sprinklers are quick response specific application sprinklers for combustible interstitial (concealed) spaces (i.e., between floors, as well as low pitch attics that meet the criteria shown in the figures in this data page). These upright sprinklers are designed for use in specific light hazard combustible, as well as non-combustible, concealed spaces requiring sprinkler protection. The glass bulb operating element and special deflector combine speed of operation and area of coverage to meet the crucial fire protection requirement for shallow space combustible concealed spaces. The Electroless Nickel PTFE (ENT) coating has been investigated for installation in corrosive atmospheres and is listed/approved as corrosion resistant as indicated in the Approval Charts.