Matthews C Clamps 12" with 2-5/8" mounting pins. Each clamp has a steel channel welded to both sides of the opening for better and safer locking. Clamps made for mounting Baby fixtures have two separate pins at different angles so that the light fixtures may fit with minimal clearance.
Matthews C Clamps are manufactured from premium drop forged steel. It should be noted however, that since the Matthews clamp is an adaptation of a standard C Clamp, there is no effective warranty on the part.