Large mouth, holds a fair amount of material, and lid seals itself once closed all the way and requires seal to be broken in order to open the lid again. Great way to store extra bulk items and ensure safety.

thus far, no problems with the c-41 chemicals I am using. I have to use some glass marbles to remove the little airspace at the top to prevent chemicals from going bad prematurely. seals up air tight. they come with a tamper ring (i guess that's what it's called) like milk jugs that once you put the top on for the first time, it breaks off so you know it's been opened. this was of no concern to me but seems like it could be a nice feature to have on some thing like this.

They were great for storage of chemicals for the dark room

I've tried 3 different brand/styles of bottles for my development chemicals. These are now my main one and I'm switching over to use this bottle exclusively. They are air and liquid tight.
I put all my chems in a plastic tote and the square bottle fits in better than a bunch of round bottles.
Paired up with a label maker I already have it's perfect to keep many various chems handy for different situations and film types.
I'm upto owning 12 of these now. Be sure to label them well. And if you have waterproof multi colored tape on top you can easily identify sets for all your dev processes (C-41, B&W, ECN-2, E-6).

These are perfect for breaking gallons of developer down into 1000 ml quantities. Much simpler to manage, pour and keep fresh. Exactly what you need when you're doing 1-2 rolls of 120 or 3-4 sheets of 4x5 film.