3/8 Stainless Steel compression shut off valve . This fitting can be used with stainless steel, copper, or nylon tubing. They are an excellent component in greenhouse misting systems, commercial and industrial misting systems, and backyard mist systems.To use, simply turn the nut to finger-tight and insert the mist line; then, turn the nut 1 1/4 turns to create an effective seal. ADDITIONAL INFORMATION UPC: 740016287773 EAN: 0740016287773