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

Perfect size was exactly what I was shopping for.

I didn’t 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 they’d 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 they’re 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 tube’s 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 Dave’s Little Beasties. I haven’t 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. They’re babies and they’re 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 haven’t seen it. Either way, I feel better knowing they have it if they want it. Especially when they’re 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 as it should

I used these to hide geocaches and they are perfect.

These are very useful!

I have to store samples in these, but they don't close properly

If you're using these for purposes other than centrifuging, they're great. They also seem fine at 10 k g for up to ~3 minutes. On longer runs, they will always rupture in the centrifuge. I've had it happen for runs at 5 mins, but generally it happens at about the 8-15 minute mark. Sometimes it will just tear the lid off and spray your sample all over. Sometimes the tube will fragment into many tiny pieces.

Works great just what I needed.