The TW16X is just one of the many accessories available for BESSEY welding table clamps. This is a variable height extension. It can add up to 7-7/8 inches of clamping height to your TW16 & TWV16 clamps and accessories. Use it with the TW28AV to create a horizontal clamping fixture that can be tilted by up to ±52°. Other available accessories are V-blocks, toggle clamp adapters and an adapter that allows you to use some of the STC series toggle clamps on your matrix table. BESSEY. Simply better.