I bought this a couple days ago, and so far it has been great. I've seen Canelo Alvarez work on this kind of bag in his heavy bag videos, but he has the "powercore" version which is still synthetic leather I believe. Heard a lot about the filling inside becoming rock hard at the bottom and soft from the middle up, have not experienced this but probably will soon. I am wondering how durable is the plastic zipper on the top? I noticed that it opened a tiny bit after I did my heavy bag workout, I really want to make this bag last as long as I can. Also, what is a good way to ever refill the bag when it gets too soft/hard? Thanks!
http://cdn.sheknows.com/articles/2013/06/Mike/sponsored/gift_7/Punching-bag.jpg
http://cdn.sheknows.com/articles/2013/06/Mike/sponsored/gift_7/Punching-bag.jpg