kirschbaum helix 1.20 for a reason i don't know and most probably will never find out i have a reel of this string in my "collection" for almost 5 years but have never strung it up to try it out. i fell in love and still have a very good opinion of the kirschbaum competition 1.20, i learned to love the mantis power poly and still consider it as being one of the best strings i have played with, but now they are not in good company, they are in better company! power/control: equalled only by the recently played signum pro gut mains 1.30/adrenaline 1.25 crosses! in spite of being, according to twu data, stiffer than both the mantis and the competition, this string has more power and plays smoother than both. each time i switched to this combo i felt that it was very easy to do whatever i like with the ball. and this test was conducted differently than all my previous ones, as i had four sticks i was rotating over the course of three weeks, the fourth string being a blindteststring from stringforum. grade: 5/5 feel: this is the only poly that, along with the competition and the mantis power poly gets the highest grade, and i would even give it a 5.1. it is really fun doing all those nasty things and succeeding at it, be it weird droppers or skidding slices or shortangled topspinshots. grade: 5/5 spin: the string is helically twisted but is basically almost round. nevertheless it produces incredible amounts of spin equalled only by the 1.20 tour bite. the profile basically wears down after some two hitting hours but there is no decrease in action on the ball. after playing with the natty/poly combo i developed a theory about this, based less on the so often cited snap-back but on the fact that given the higher power of the strings one tends to control them by adding rhs and thus invariably produce more spin. this definitely holds true for heavy topspin hitters as i happen to be, for flatter hitters results might be different. grade: 5/5 comfort: absolutely no issues here, plays smooth and nice even on offcenter shots. grade: 5/5 tension maintenance/durability: the string lasted close to 4 hours but since i played it over the span of three weeks i can also tell that it kept it's playing properties very well over the entire timespan. grade: 4/5 overall grade: 24/25 after having played last year tournament matches with 7 different string-combos in my bag, i decided to take a different approach this year and keep three "competitional" sticks strung with the same combo and the other four for testing purposes. so, starting this coming week i'll swing the helix in my competitionals.