PPR plastic barbed fittings can be easily attached to the water heater. Made of PPR and stainless steel, no fading, no cracking, longer service life. Smooth surface and inner wall, durable and lightweight. Exquisite craftsmanship, safe and reliable. Material: PPR + stainless steel,Type: 1/2", 2/3",Inner diameter: 20mm/0.8in Tip: Plastic barbed adapters/connectors can withstand temperatures from -9°F to 175°F, but are not oil resistant.