SPG 5/16-1/4 is Pneuflex' model number of 5/16 x 1/4 inch union straight reducer - stainless steel push to connect fittings. Use it to connect tubes of different diameter of 5/16 inch and 1/4 inch. Composed of stainless steel body and 301 SS lock claw & FKM ( Viton ) seal, these durable SS union connector reducer push-in fittings can transfer air, water, oil and weak corrosive fluids.