Super Quick Clamps, the more efficient, less costly clamps that replace 4", 6", 8" or 12" C' Clamp! The movable sliding arm saves 90% of clamping time vs. a "C" Clamp. Deep throat (4-3/4" on the SQ-4 and SQ-8, 5-1/2 on the SQ-12) has greater reach, eliminates having to buy both regular and deep throat "C" Clamps.