100% graphite ferrule; upper temperature limit 450 deg.C. Soft; graphite is recommended for use with fused silica and glass. Reusable if not overtightened. For use with standard 1/4 in. Swagelok / Parker type fittings. One piece design requires no back ferrule. Packaged: 2-3/8 in. x 1-1/4 in. x 1/2 in. Plastic Hinged Box; Weight: 17.0 g.