You can go "green" and buy recycled targets. I don't know what the core is made of but I shoot these in by basement regular @ 10yds and my arrows stop at around 8" penetrated with my Z7. This is by far the best target for the price.

Specs:
24H” X 20H” X 12D" 20lbs

http://cgi.ebay.com/Lightning-Stop-F...item4aa1c6e1ef