This two layer circuit rig may look plain but it is anything from plain. This small oil rig creates a smoke circuit through the two chambers that cools and diffuses hits, creating a vortex effect within the rig.  The two layer circuit rig is made out of borosilicate glass, the tubing on the circuit rig is 60mm tubing with an angled mouthpiece, 14mm quartz domeless nail, and two double-decker bubbler chamber this will allow the smoke to cool down and be filtered.