Sigma ProConnex 3/8-in Flexible Die Cast Zinc AC/Mc Connector Conduit Fittings (10-Pack) in the Conduit Fittings department at Lowes.com
4-Inch Square Metal Box with Side Mounting Bracket, Welded, 1-1/2'' Deep, with 2 AC/MC/Flexible Cable Clamps, Three 1/2'' knockouts, 1 TKO, Combination Screw Heads, New Work - Amazon.com
Snap2It® MC Flex Cable Connectors w/ Ground — Primus Cable
MC cable supports | AC cable fasteners | flexible conduit support | Eaton
Southwire Clip-It MC/AC 12/2 thru 10/3 Conduit Clip (100-Pack) MAG840 - The Home Depot
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
Steel, 1/8 in to 1/4 in, MC/AC Cable Beam & T-Grid Clip - 2KWW2|MAC224 - Grainger
Learn the Basics on How to Work With Metal Clad Cable
4″Octagon Box, 1-1/2″Deep With MC Cable Clamps (50Pcs) – QB Electrical Supplies Inc.