Hellermanntyton non metallic conduit flame retardant hg fr range hellermann tyton 166 11404 the hellermanntyton helaguard 166 11404 hg fr28 is a non metallic conduit from the hg fr range the conduit is highly flame retardant highly flexible and has a high fatigue life ideal for applications in railway vehicles railway tunnels underground stations and public buildings where high fire protection is required hellermanntyton 166 11404 hg fr28 pa6 flame retardant conduit 28mm