HYDRA OMNIVONG XL: LIGHT WOOD: Variable Vapor Flow Adjustment just like the OmniVap, this model includes a 14mm Dark Wood HydraVonG Stem midsection with Omni Mouthpiece assembly. With the 14mm taper built into the stem, it mates perfectly with most 14mm adapters. The Omni system has a specialized design to allow for simple adjustment of flow restriction, allowing complete control of the vapor to air intake ratio. Adjust by simply twisting the mouthpiece, which extends/retracts the condenser into the back end of the tip. It is not compatible with the M Tip or body midsections.