This is a portable punching bag that can be adjusted from 47 in. to 56 in. The bottom is about 4 gallons I’d say, and can be filled with water, sand, etc. The actually punching bag is filled with an air pump that comes with it. It has a spring on the bottom so when it’s punched it will come right back for another punch. It’s recommend for ages 6 and up. It also comes with a pair of very large boxing gloves that offer lots of cushion, but my hands got very sweaty very quickly in them. I liked this punching bag, mostly because it’s portable and was really easy to put together. I filled it up with water and was able to punch and kick the thing so hard it would fall over. I recommend filling it up with something heavier than water, except if your getting it for a kid. I also enjoy kicking the thing, although make sure you know what your doing or your wear shoes because hitting the metal bar with the top of your foot will hurt. I recommend this punching bag to anyone who just wants something to beat the crap out of.