Taking a standard 10" Clamp and adding Speed Rail fittings makes this clamp one of the most versatile. Clamp adjusts from 10" to 20". Riding on standard 1-1/4" Speed Rail this multi-Purpose clamp can make any rigging challenge easier. Matthews C Clamps are manufactured from premium drop forged steel. It should b e noted however, that since the Matthews clamp is an adaptation of a standard C Clamp, there is no effective warranty on the part. Black only. Shown here with speed rail, not included.