After the first 10 minutes already regret buying, who buys cheap, buys twice! The brackets come Sporat, then 2 times or. After about 20 clamps the tension spring jumped as it strikes for the 1st time. then continuously, thus verutschen the brackets and make cross itself. Device is useless. Yet to use, I wanted vapor barrier on wooden rafters tacking. So rather spend a few more euros. Actually is 1 star too much!