HeatigoSolid Rubber Stopper, 30 Pack White Solid Rubber Stopper Laboratory Rubber Plug Pipe Tank Bottle Push-in Sealing Plug Tapered Hole Bung, 000# - 8# Sizes Assortment, 11 Assorted Sizes

Brilliant. Solid product, plugs perfectly and no need to worry about breakong them like the glass stoppers. They y let nothing escape and come in many useful sizes. I would say sizing should be given more precisely and perhaps with indication as to which lab flask neck size it fits - stoppers are labeled with simple numbers from 1 to 10, not like flasks eg 29/40 etc which could be a useful improvement. Otherwise perfect. They withstand high temperatures, chemicals, cutting, drilling,falls and other harsh treatment.

Just like they say on the tin. Bought a bag for one little job because I'd no idea what would actually fit but now used them on two other things. Surprisingly useful

I needed a couple of stoppers for different applications and wasn't sure, precisely, what sizes I needed. This was a good selection that met my needs. I'm sure folks who buy these things all of the time understand the sizing nomenclature but I would have found it useful to know top and bottom diameters and length.Product is excellent, well made and each stopper labelled with a size code. Delivery was immediate

Seems reasonable product.

100 %,thanks.