Halex 3/8 in. Flexible Metal Conduit (FMC) Combination Clamp Connector Standard Fitting (5-Pack) 20570 - The Home Depot
Sigma ProConnex 3/8-in Flexible Die Cast Zinc AC/Mc Connector Conduit Fittings (10-Pack) in the Conduit Fittings department at Lowes.com
How to Use Armored (BX) Electrical Cable: 11 Steps (with Pictures)
Bridgeport 566-DC2 3/8" Two-Screw, Strap Type MC/NM Connector, Zinc Die Cast. For connecting 14/4 to 10/3 Armored, Metal Clad Cable, or 14/2 or 12/2 NM-B Cable | Cooper Electric
2 Way Electrical Junction Box, La Vane IP68 Waterproof 2 Way Cable Connector Lighting Connector Electric External Coupler, Cable Gland Ø 5-12mm - Amazon.com
Junction Boxes for Steel Armoured Cable - Bradshaws Direct