3/4 water check valve Backflow Preventer Plumbing Boiler Irrigation Plastic 1 In

I have some sort of check valve or backflow preventer not really sure what it's used for it's brand new 3/4 in on one side and 1 inch on the other and also a 1-in opening on top it does have a bleeder that's brass and a brass bottom plate look at photos carefully. For plumbing irrigation Boiler Room backflow check valve. Item is about 6 in tall and 4 in wide

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