DEPRESSED CENTER GRINDING WHEELS REDLINE CBT™ CERAMIC BOND TECHNOLOGY Higher stock removal rate than Zirconia! Pearl’s Ceramic Bonded Technology™ (CBT™) grain is a non-fused ceramic aluminum oxide that is extremely strong and durable. It is a very fine crystalline structure, which allows for micro-fracturing of the abrasive grain. This promotes constant generation of new grinding edges allowing for longer life and faster stock removal throughout the entire life of the wheel. In addition, CBT™ grains perform exceptionally well on stainless steel.