Conduit connectors

A connector 1 for connecting a conduit to an aperture in a barrier; the connector body having a stem 9 for connection at a first end to a conduit, and a flange surface 13 around a second end of the stem for sealing against a first side 5a of the barrier; the body having a lumen 17 extending through the first and second ends of the stem; a collar 19 having a bore 21 sized to receive the stem, and one end of the collar having a flange surface 23 around the bore for sealing against a second side 5b of said barrier; the stem and the collar configured to together define a retention mechanism 27 (e.g. a ratchet mechanism) when the collar is placed over the stem, to resist movement of the collar towards the first end of the stem. Embodiments include the above wherein the collar and/or stem comprise a severable portion, which in use can be preferentially severed so that the connector can be removed from the barrier. May be used for the connection of vacuum or resin injection hoses through a vacuum bag or tooling cavity during manufacture of composite articles.