In the bad old days when I was soaking Tristan's foot every single day, trying desperately to draw out the abscess that we thought was just stubborn and/or trying to keep the abscess holes clean, soaking was a chore. I used the tried-and-true feed pan method. Result: guaranteed spillage, frustration, and possibly tears. (If you want the whole abscess drama in real time, follow the abscess tag and then the surgery tag.)
One day, I found myself at Smartpak to purchase more Betadine and epsom salts, and cleverly placed alongside those vital supplies was a Davis soaking boot. It was $32.95, and as we know that is pretty darn cheap for something connected to horses. So I bought it. And it changed my life.
Some of the advertising for this boot seems to imply that you could, in theory, fill it and then turn your horse out in it. I believe that to be creativity bordering on bullshit. If you have a boot large enough to hold an appropriate amount of water, it's too large to stay on your horse. Also, it would get trashed, durable as it is. So don't do that. If you truly desperately want something to serve as a hoof dressing during turnout, do the old duct tape method and plan on replacing daily. But if you are looking for a way to make your life easier while soaking, buy one of these. It's a game-changer, and no barn should be without one.