The ladder perc was created by Micah Evans, a senior designer on GRAV® product development team, and is one of the signature features of the Upline collection. The perc consists of a series of stacked bubbler chambers, separated by extra-thick restrictions. Water from the lowermost chamber is pulled up with the smoke stream when the pipe is smoked, literally climbing the pipe like a ladder. Each chamber can only hold so much water, referring any excess farther up the pipe. This turns each chamber into a small bubbler, powerfully washing the smoke as it ascends. Due to its small size, relative simplicity, and the ability to incorporate it into most pipe formats, the ladder perc is one of the most efficient glass percs available.