Kesell 20-Pack 20ml Glass Vials with Screw Caps - Small Vials for Essential Oil, and Specimen Samples - Clear Bottles with Lids

First off I'll say the claim by the listing/manufacturer that these are "leak proof" is false and I don't even know how you could say that they are with absolutely no type of seal, it is literally just a plastic cap and small glass bottle. That said, the first bottle I tried leaked as I thought it would, but two wraps around the treads with plumbers tape fixed it no problem. I'm just going to do that from now on. I think even if you had one that didn't leak, plastic contracts and expands depending on temperature so there is a possibility of it leaking later on unless you seal it properly. It was 74 cents for a roll for some peace of mind, just do it.The glass is good and clear, they are a good size for a relatively wide array of specimens, and the plastic cap means there will be no corrosion or evaporation of storage chemicals like you have with cork and metal. The glass is also relatively thick and good quality. I didn't have any break during shipping.

Exactly what I was looking for. Perfect size for my needs. Sturdy glass.

These are nice small jars for element sample storage.

Always excellent serviceThank you

I purchased these vials for use in creating a specimen collection of aquatic invertebrates. I teach a course of field stream macroinvertebrates to young budding scientists that focuses on the systems integration of aquatic life with the natural environment. These vials are exactly what I need to allow students to get up-and-personal with the invertebrates. Clear, right size, and perfect. Dr. John