CR-31 installation accessory is available in gold or chrome. CR-31 installation accessories are suitable for fibres C-Flex / S-Flex 2 - 4 with an M8 end fitting. CR-31 access hole diameter is ø 14 mm and the external diameter ø 18 mm. The length of the crystal part is 31 mm. The installation requires 35-45 mm of free space behind the ceiling or wall surface.