... 2.Factory direct sales 3.Price concessions 4.Fast respo High quality fire sprinklersZST-glass bulb sprinkler consists of glass balls, copper ... , nominal diameter: φ 15 mm, connected to thread: R1/2 ", the flow characteristic factor: K = 80 ± 4.2, nominal diameter: φ 20 mm ... , connected to thread: R3/4 ", the flow characteristic factor: K = 115 ± 9.3, rated pressure: 1.2 ...