I have used a celcius bale(synthetic hay bale) for years, but it's shot out at this point. I was thinking of replacing it with another, but shipping cost were prohibitive. Then I thought about the roofing resin board sheets. Cost was going to be about $100. Then my wife said let's replace some carpeting and well all I thought was target! I had previously researched carpet targets, so this wasn't my idea. This was an easy project and free in my case. I measured 40" and cut the carpet in lengths to remove it from the rooms. My technique was to lay the carpet on a cement floor with the backing up. I then laid a 2x10x50" on the edge and used the other side as my cutting guide. Move the board and repeat. My arrows from my indoor bow penetrate it about 6". I put the old celcius bale behind it just in case. Tightening the clamps would limit penetration even more, but right now some arrows only go in 3". Finished shooting area is 38"x38".