I wanted to see how the Blackburne double strung racket would behave with a bit lighter head, so I picked up some Head Power Fibergel and 19g Gamma TNT Fusion string to try out on it. I had heard the Power Fibergel was really light. I believe one poster had these strings at about .17 oz lighter than a normal 16g gut, so I thought I might loose .3 to .4 oz with two sets of this string. I also thought the 19g TNT should be light, though it includes a cross with 17g string. Testing the weight of different strings at the post office they all came in at about a half an ounce. These were all out of the package but with the little plastic twisty still on them. The 17g Gosen sheep actually looked a little lighter on the scale.This was a non-digital scale so I am just looking at the analog arm being about between the 0 and the 1 oz. I didn't meaure the actual string length but they all said they were 40'. I strung one double strung racket with the Fibergel on one side and the 19g Gamma TNT on the other side and it came out a couple tenths of an ounce heavier than the identical racket with the original 16g synthetic gut still in it! I didn't measure these rackets without the string in them, so maybe they were a bit different from the factory. Maybe I need to buy a tenth ounce digital scale to get more accurate readings, but from what I can see so far, these strings aren't appearing to be lighter than other strings I have been using.