1/16" Ferrule (long) 85% Vespel / 15% Graphite (10/pk).85% Vespel / 15% Graphite ferrules have an upper temperature limit of 400 deg. C. 1/16 in. ID (1.5 mm) is for 1/16 in. OD tubing; ferrule fits into standard 1/16 in. Swagelok / Parker type fittings. One piece design requires no back ferrule. Ferrule size is approximately 3.5 mm long and 3.0 mm in diameter.