This site has the 9 best punching bags for kids ! I really like the one that's number one ! All can be purchased from Amazon.
Top 9 Best Punching Bags for Kids Reviews 2015 - iBest9
what are the best punching bags for kids?
There are different brands that have boxing equipment's , boxing gloves , punch bags etc.You must visit on: http://rdxsports.com/corporate/blog/amazing-punch-bag-training-for-your-9-to-5-life-for-fat-burning/