Wholesale GRAV Labs 9" Bell Base - Clear The GRAV Bell-Based Water Pipe is 9" tall and made on 32mm tubing. Its downstem ends in a broad orb perc that diffuses smoke through water and is fixed inside the pipe to prevent damage. The tiered body keeps water from splashing out of the piece. The bell-based water pipe comes ready to use with a 14mm GRAV Cup Bowl and functions best with approximately 2" of water