I got the orange buoy in
@Woldog's picture (ie the Polyform A5).
It's 27 inches in diameter by 36 inches tall.
I can't remember how many gallons of water that works out to, but it was supposed to be over 400lbs filled.
Hanging it was tough.
I bought some 6" by 8" lumber to straddle across 2 ceiling beams and hang the bag mount.
I secured this makeshift joist with extra strength zip ties and some L brackets.
The mount itself was an 1800lb capacity swing hanger.
To extend down from the mount I got 1200lb-rated M8 steel carabiners.
I also tried a hammock chair spring rated to 660lbs, but that actually stretched out pretty quick.
Finally, I got a 1inch, 8.5 ton rated Titan Bow Type Anchor Shackle (nothing else would fit the hole in the buoy).
I had some painful lessons learned in this one:
1. make sure you get a gas siphon pump in case you need to empty water
2. do NOT fill more than half way, the buoy will stretch a lot if you do (especially the mounting hole). i imagine it will eventually break.
3. it's better to hang it higher than you would initially guess
4. related to #3, punching on the top half of the buoy will likely lead to wrist injuries
After all the work & expense in hanging it, I gave up on it after I realized that punching it was just not an enjoyable experience.
The roundness of the buoy meant that i was constantly worried about hitting at a bad angle and snapping my wrist.
It was so wide, that I had to flair my hooks if I didn't park myself outside the bag.
In the end, I went with a 5' 150lb bag from Pro Boxing Equipment and have not regretted that choice for a minute.