What you need:
Wine corks that are roughly the same height.
Hose clamps from hardware stores.
Screwdriver the tighten the hose clamps.
Arrange the corks inside the hose clamp. Tighten. You may have to adjust the corks repeatedly until you are finished tightening the clamp.
I think these are a cheap, cute touch to any kitchen. I use mine all the time!