Viking Model A-1, B-1, and C-1 Sprinkler Water Shields and Guards are used in conjunction with Viking frame style 1/2” or 3/4” NPT (15 mm or 20 mm BSP) upright or pendent sprinklers where allowed by the approvals. (Refer to the Approval Chart on Technical Datasheet page 130g). The guards are hard-wire cages designed to encase the sprinklers and protect them from mechanical damage.