bass trap material question

I want to build something like http://www.realtraps.com/these.... what material shoold I use for the absorption??? I want to buy some Rockowool material... the complete list od product is here http://www.rockwool.cz/sw2836.asp it is spoken about STEPROCK (T or L ???) but is it better than others like rockmin or domrock??? I will not do the holes in the wood frame in the absorber for better absorption. absobtions should me still good didnt it?

I'm sorry, but your english is much better than my Czech - I could not get enough info from that site to understand what their products are. What you need for the inside of bass traps is a rockwool product that has a density of 40 to 50 kG per cubic metre - the thicker, the better as long as it does NOT touch the front panel. The realtraps are a commercial sale item, not for home building - maybe you were planning on building some of these? http://www.ethanwiner.com/basstrap.html There is a link on that page that takes you to actual plans. I hope that helped... Steve