Karter Scientific 250ml Glass Round Media Storage Bottles with GL45 Screw Cap, Borosilicate Glass, 251L3 (Pack of 2)

Used some of the 10 bottles I ordered (I ordered 5 sets with 2 bottles in each, at different times, I believe from the same seller) and they did well in autoclave for 4 cycles sterilization in a row (the autoclave was having issues and it stetilized the bottles in a series of repetitions, by the error) and the caps, nor the glass got damaged in a process in extended periods of high pressure and heat!This suggests that they are great quality.The design itself is good, but there is some accumulation of moisture even in the dry bottles, so I suggest to sterilize them on the tray without any moisture to prevent that. I will watch for any contamination issues, but they seem so far not leaking.I did sterilized ddH2O in some as well, and they probably will be used mostly for these and small volumes of media storage, such as molten agar for short term storage.I will update if any functionality is affected, but so far, for the price, these are great addition for small volume media storage, such as molten agar, small volumes of reagents that you might need to keep in several bottles to prevent contamination from reopening (such as liquid media for culturing) and some frequently used reagents/solutions/stetile water.I haven't used them for any dry powders, but if they are planning on doing so, I sugest to dry them well after 1st stetilization and use them then (if you don't need to keep the powders sterile, or resterilize the 2nd time of the dried bottles. I would make sure to keep the tape on both sides of the cap as they unscrew a little more than the other media bottles I used to prevent contamination.I haven't measured them exactly, but the opening on these is the standard as in the larger bottles as these caps fit on the other larger bottles.In a summary: great 100ml bottles for small (60ml mark is at half the bottle, so you can easily go for 50-60ml volumes in autoclave if using them for solutions/water/media) volumes that are inexpensive and good quality for its purpose.

Everything you want for a bottle that could potentially hold harsh chemicals is here. The tops screw on tight and are sealed perfectly when closed, no leaks whatsoever and they are air tight. They can pour liquids very nicely without the liquid going everywhere even though there is no "spout" or anything like a beaker would have, not sure how but they pour as well as a beaker or better with no liquid running down the side or going where you don't want it. The borosilicate glass is thick and will withstand any chemical you throw at it (except hydrofluoric acid obviously, don't use that in glass) as well as withstanding temperatures normal glass will not. I could see a lot of uses for these outside of holding liquid chemicals that need a leak proof borosilicate bottle, maybe moonshiners might like them (probably the larger sized version of these same bottles, which I also bought and am also very happy with) or for the rest of us non moonshiners, maybe holding or mixing other beverages as you can shake these without fear of spilling. Any liquid you need to hold except hydrofluoric acid (sorry Walter White) these will do great and they come in whatever size you could want.

Seems fine so far

These bottles are as advertised, but look at the pictures so you know what you're getting, specifically the cap. The inner ring does make for dripless pouring. But the hard plastic-on-plastic seal means it needs to be fully tightened every time. It is not like a rubber seal - if you stop tightening when you get resistance it *will* leak. The cap also retains a lot of liquid. If you have a sample in suspension and shake it before opening it's very hard not to drip some.

Fast shipping and as described. Thanks!

I've ordered 500mL media bottles from Karter before with no issue, all bottles were accurate to their description. The 250mL bottles, however, are not.At the bottom of the glass, you can see it has a 2 on it. If you didn't know, this classifies it as treated soda-lime glass. Real borosilicate glass, which is specifically used for its heat resistance, is type 1. You would see a 1 at the bottom of the bottle.I'd chalk this up to a mixup in the delivery process if it were not for all the other reviews posting about broken glasses after heating and even a few also pointing out that these are not true, heat resistant, borosilicate. Because of this, I'd say this is blatant false advertising on its face.And DANGEROUS false advertising at that. If you were to heat up one of these too quickly, they have potential to shatter, possibly causing cuts and even burns if there was any heated liquid inside the bottle. Instant 1 star, I'd give it a 0 if I could, just based on the safety hazard alone.

Exactly what I ordered. Well made. Well suited for purpose.

perfect size, wash well, no deforming in hot cycle of normal dishwasher, lids seem to seal. excellent quality for price.