3/8" compression thread x 7/8" plastic ballcock nut. 1 per card. Flexible - Polybutylene may be shaped, contoured or looped to fit any installation requirement. Pressure rated with a burst strength of 900 P.S.I. of 150 deg. NSF, PWS, E listed, CSA B137.8. Exceeds ASTM 3309. Dependable 1-piece construction with formed self-sealing heads. No crimps, fittings, O-rings, or compression sleeves to fail or leak. Solid brass connecting nuts on each tube. Tube size on all connectors 3/8" O.D. x 1/4" I.D.