100 Pcs Centrifuge Tubes 1.5 ml Bottom Tip Clear Plastic Test Tube Vials Small Tubes with Caps Small Sample Bottle Vials Container with Cap for La...

I used these to hide geocaches and they are perfect.

These are very useful!

I didnt buy these for use with a centrifuge. I bought them to use the caps as water dishes for tiny invertebrates. That said, they seem good. The caps all seem to fit their tubes well. Each one has so far been identical to the next; no irregularities in the manufacture. The plastic is firm but flexible and a good thickness. I imagine theyd work well for their intended purpose. They also work very well as tiny water dishes: I cut the caps off the tubes, trim the cut sections so theyre smooth and set them on their tops. The wide brim makes them easy to open, but also makes a great base. The round section of the cap, that sits inside the tubes opening and seals it when closed, makes a perfect reservoir for a few drops of water. Great for 1/4 - 1/2, maybe up to 3/4 tarantula spiderlings who need access to water but misting regularly may make their environment too damp. If the strip of plastic connecting the cap to the tube were cut to a point, it could also be used to sort of stab into a bit of cork to mount the cap higher up for an arboreal spiderling or other small invertebrate. Again, the wide brim on the cap comes in handy as an extra foothold for the animal to stand on while drinking. Got the idea from Daves Little Beasties. I havent seen any of my slings drinking from them, but better to have access to water and not need it, than need it and not have it. Theyre babies and theyre still quite shy. What they get up to after the lights have gone out, who can say? They may drink from these regularly and I just havent seen it. Either way, I feel better knowing they have it if they want it. Especially when theyre coming up to a molt and refusing food. Internal hydration is far more important than the ambient humidity when it comes to spiders molting. (Ambient humidity is still important, but) Anyway, whatever you use these for, they should likely work well for you.

Works great just what I needed.

Just a bunch of cheap centrifuge tubes. The connection between the cap and the tube can be fragile, but that doesn't really matter. They don't seem to leak, even after a long time.