ANPTGHT 1/2” Thru-Bulk Bulkhead Plastic Hose Barb Fittings Union Adapter Fittings for Aquarium Fuel Gas Liquid Air with Metal washers (Pack of 6)

It's a little annoying that they aren't included, but those cheap garden hose rubber washers, between the metal washer and the wet side, really make this pack of fittings great. Hope you have some laying around the house!