Currently all tips have undergone an upgrade. I have added a stainless steel stem so now the tips have a stainless steel core and stem. This will eliminate the possibility of the stem breaking below the o ring. This will also give a much more consistent fit with a wide range of manufactured 510 connections. If you own a drip tip that I made before I started using the Stainless Steel connection I can upgrade your tip to this new design. Just contact me and I can give you more information.