Thought this world be great since I try and keep my pieces clean as much as possible. Always hated plugging with my finger. While it does what it's suppose to, the glass is very poor quality. In the male insert end you can see a big air bubble. One the "top" circle there's many little air bubbles and one pretty good size on at top edge that almost looks like a crack or chip. Now I'm sure these are very random, if you had a box of them to go through I'm sure you could find some flawless ones and there's probably worst ones. Good luck on getting that good one if you order.
will not seal for cleaning
will not seal for cleaning. both sizes leak.