Reducing Casings 16 -> 28 were especially developed for clamping 16 mm components onto 28 mm tables using 16 mm bolts. Using a 16 mm bolt, the Reducing Casing is fixed onto a 28 mm table, thereby providing the opportunity for bolting on a 16 mm clamp element. The Reducing Casing is suitable for 28 mm bore holes, but not for 28 mm oblong holes.