Sigma ProConnex 1/2-in Die Cast Zinc Cord Grip Connector Conduit Fittings in the Conduit Fittings department at Lowes.com
ASI 3001225 Nylon/Plastic Cable Gland, Strain Relief Cord Grip, Type 1900.M20, M20 x 1.5 Threads, 25 mm Nut, 7 mm to 13 mm Clamping Range (Pack of 100) : Amazon.co.uk: Business, Industry & Science