I wish I was smart enough to get into detail (then again, Mr. Danielson might not want his trade secrets disclosed).These new limbs are supposed to be faster than my 1 yr. old limbs due to the new constuction. I do not have a chrono and it wouldn't matter because these are 38# recurve limbs. My current set up is a 58" 50# Black Swan hybrid based on the 13" modular riser. My plan is to set up a 17" riser with recurve limbs for form and target work making a 62" bow. They are realy cool looking if you like "techno-trad". I was shooting arrows tuned for a 53# longbow, upped the point by 25 gr, and got good flight so the efficiency of the limbs is very good.