DT65-9. Glass 2-In-1 Drip Tip + Top Cap Combo for 20mm Tobh Atty V2 RDA Just remove the top cap of your 20 mm version Tobh Atty V2 and install this device Mouthpiece diameter: 18 mm Connecting joint diameter (w/ O-ring): 20 mm Price: $3.25 Unit: Each Quantity: