Our handy tubing selectors will end doubt about inside or outside diameters when choosing the tubing you will use for a job. The tubing sizers gauge measure glass and plastic tubing, connecting pieces, rods, test tubes, and more over a range of sizes, measuring both the inside and outside diameters. Made of propylene, these gauges are autoclavable.
SP Bel-Art Stopper/Tubing Sizer, Bel-Art Products, a part of SP
Handy stopper/tubing sizer easily determines the correct size of the cork or stopper needed for any flask, bottle, etc.