Main technical data ¡¡ Diameter Dn15 dn20 Material Zinc alloy or brass Response time 15seconds in general for 5mm glass bulb 8seconds in general for 3mm glass bulb Response time index rti (m¡¤s)0.5 87 for 5mm glass bulb 22 to 25 for 3mm glass bulb Flux coefficient 80 for dn15 115 for dn20 200pcs/carton