dry drill core bits for brick, block and masonry - 4" diameter 5/8"-11 threaded #30/40 diamond grit ediamondtools #30/40 diamond grit, premium quality, designed for drilling masonry, block and soft brick - diameter: 4 inches - thread: 5/8"-11 threaded - drilling depth: 9.5" - high diamond concentration and quality guarantee longer coring life.