M6 Snowboard inserts are sold with a plastic covering to keep epoxy
out of the threaded socket during fabrication. The ones with the clear
cap are 7.5mm (total height), and the ones with the red cap are 6.0mm.
The hexagon base is 9mm on each side, and the collar has an outside
diameter of 9.5mm.
Available from SnowboardMaterials.com