OPW 66V-0300 breakaway valve must be installed in a more than 9 " hose, when under tension, breakaway valve will be torn apart, two valves automatically return, cut off the oil flow to prevent oil spilling, to protect fuel dispenser. 

valve body:aluminum 
spring: galvanized spring steel spring.
connector:Zinc
seal: FKM, NBR
size: 3/4 "FX3/4" f "(NPT) 
weight 0.27kg 
pull: 300lb