Hattersley gland cocks / drain taps are small isolation/drainage fittings made of bronze or DZR brass, used to drain system sections or remove sediment without disassembling pipework; for example, the Fig. 81HU gland cock is rated PN10 up to 10 bar and 0-120 °C, while the Fig. 370/371 draining taps are WRAS-approved DZR brass units rated to 16 bar up to ~110–120 °C.