I have not had good luck with my first 2 Sapphire Buds. I have used them both on 2 different batteries both are EGO 510 connection 650 mah 3.7 volt. I am a long time CE2 clearomizer user. Both Sapphire Buds got extremely hot at the atomizer and heated up both batteries to being uncomfortable to touch. I thought I was going to burn both batteries out. I tried to pull the drip tip cap off one of the buds and the plastic tube came off the atomizer. Maybe because the plastic was so hot it had swollen up at the bottom. Both developed a bad burnt taste before I finished the first tank of liquid. I removed the inner fill cap hoping to let more air in and the burnt taste seemed to go away. The fluid continues to run into the air vent creating a gurgling sound and very little vapor. I have read a lot of really good reviews so maybe I just don't have the right batteries yet. I have not completely given up on these yet. I have ordered the EGO Sapphire Kit and am hoping the Sapphire Buds will work better on the EGO batteries that are in the kit.