100% Vespel polyimide. Upper temperature limit 350 deg. C. 0.3 mm ID fits 0.18 mm ID and narrower capillary fused silica columns. For 1/16 in. Swagelok / Parker type fittings. One piece design requires no back ferrule. Packaged: 3 in. x 3 in. x 1/4 in. Plastic Dial Pack; Weight: 8.5 g.