I used to be one of the guys that said all you need is B-50, or B-55, Dacron material, you know? Anyhow, I just decided to give this "new" Dynaflight 10 a try and the long story short is, it's what I'm going to use from now on. I've made lots of strings, I've made lots of bows, and I've only made one string with the D-10, it was for my 48# longbow. I made a 10 strand string, and found that compared to my 9 strand B-55 string, with the same brace ht. and same two arrows, my group is half the size and penetration into the same target was about 3" more with the D-10. Also the brace ht. stayed where I started. If it stretched it wasn't worth measuring. I've always said to stick with the tried and true, and you can't make a better mouse trap, but this D-10 is truely amazing. But be sure and only use it on bows that have reinforced tips that can stand up to it.