Several hits in google while searching for '4 core flex'
https://www.tlc-direct.co.uk/Produc...qpoFAwRs03FAwUVtivkna5BDNBvAs7yRoClP8QAvD_BwE
https://www.electricalworld.com/en/Zexum-05mm-4-Core-PVC-Flex-Cable-White-Round-2184Y/m-676.aspx
https://www.sparkshop.co.uk/1-0mm-3...ulated-and-sheathed-flexible-cable-white.html
http://www.kmts.co.za/Main.asp?D={B...pe=Product&CategoryID=196&SKU=MLSW04+++++++++
https://www.greenmillac.com/Products/Electrical-Cable/Envirotuff-Cable-1-5mm-4-core-100mtr.html
https://www.tlc-direct.co.uk/Produc...qpoFAwRs03FAwUVtivkna5BDNBvAs7yRoClP8QAvD_BwE
https://www.electricalworld.com/en/Zexum-05mm-4-Core-PVC-Flex-Cable-White-Round-2184Y/m-676.aspx
https://www.sparkshop.co.uk/1-0mm-3...ulated-and-sheathed-flexible-cable-white.html
http://www.kmts.co.za/Main.asp?D={B...pe=Product&CategoryID=196&SKU=MLSW04+++++++++
https://www.greenmillac.com/Products/Electrical-Cable/Envirotuff-Cable-1-5mm-4-core-100mtr.html