Mu Tian Bonsai Tools Round Edge Cutter 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.