An integrated part of the Pulsar RöK, the borosilicate glass downstem replacement part is available in case the original downstem was mishandled or neglected. This certified replacement downstem for the Pulsar RöK Electric Oil Rig is made with durable borosilicate glass and features a cyclone style percolator. This style of perc swirls the water as it bubbles and percolates the vapor to create ultra smooth hits from your rig