Gibraltar SC-GRSMC Road Series Multi Clamp Go to amazon.com Related posts Thing need consider when find gibraltar clamp? FeatureFor mounting toms, accessory arms (5/8" to 1-1/4" diameter) to standard 1-1/2" diameter rack tubes. DescriptionFor mounting toms, accessory arms (5/8 to 1-1/4 diameter) to standard 1-1/2 diameter rack tubes.