I bought this 26 blades Wür my Bosch ART 18LI battery trimmer, with the befürchtund that they must be replaced after each use. For more than about 8 weeks I have still the first blade in use even after a few strokes, and against Szteine Hauswand the blade is indeed vermackelt something but nich gebrochn as feared. I binm pleasantly surprised and can only recommend the blades.