Mu Tian Bonsai Tools Round Edge Cutter Made By the Carbon Steel Mixed Function of Round Edge and Straight Edge Intermediate Quality 180 Mm (7") Material is 4Cr13MoV (Stainless Steel Tool) and High-Carbon Alloy Steel (Carbon Steel Tool), handmade by professional technicians from TianBonsai. Hardness is over HRC55, also with high intensity, strong tenacity and wearability. Quality Assurance: 2 Years, in normal use, if the tools have any problem, we will resending a new one to you without any fee, you just need to take a photo to us to show the problem.