Sigma ProConnex 3/8-in Flexible Die Cast Zinc Snap-in Connector Conduit Fittings (25-Pack)The Sigma ProConnex Double Snap Lock AC MC Connectors are used to terminate AC, MC or FMC RWFMC cable to a knockout in a dry location box or enclosure. The patented design has a pre assembled throat insulator and requires no tools for faster installation. These die cast zinc connectors are suitable for aluminum or steel conduit. Terminates AC, MC or FMC RWFMC to a 1 2 in knockout For aluminum or steel 14 2 10 3 AC, 14 2 10 3 MC (MCI, MCI A, HCF and