Standard beer bottles, and they are as durable as you would need. I have yet to break one when handling them with normal care, and have not had one burst during carbonation. Other than shipping issues, they stand up as well as expected.

Update – After using them a few times, and purchasing more bottles from a different manufacturer, I decided to raise my review to a 5. I have yet to have any of these bottles break while capping or in storage, and I have used them 5+ times each. I had several of Brand X break the first time I tried to cap them. After a suitable ceremony over wasted beer, I vowed to never buy anything but these bottles again.

I ordered these for bottling my own home brew beer. At the time, I was looking for free bottles from a few of the local bars, but I wasn’t able to find a very large number of pry-off top bottles, so I ordered these. I incorrectly assumed that these were pry-top bottles because of a reference for these from a home brewing forum. These are, instead, twist off bottles. Overall, they are a nice, high quality bottle and they were packaged exceptionally well. I’m even planning on using the included styrofoam packaging to neatly organize my bottles, but I wish I would have known they were twist off. I only received the bottles a day before I need to bottle my brew, so I’m going to go forward with the bottling despite what I’ve read. I hope it all goes well.

I’m knocking one star off for the incomplete description, but other than my twist-off/pry-off problem, I think these are a high quality bottle especially considering the price.