Large blocks are offered in sizes up to 2 meters by 2 meters by 2 meters. They are offered in either K4A (equivalent to Schott’s ZKN7) or H-K9L (Equivalent to Schott’s (N-BK7).

The two largest surfaces of the block are fine ground and the other surfaces are coarse ground. The edges and angles are chamfered. All blocks are fine annealed.