Knob Cutter Beginner Bonsai Tools Made by Carbon Steel Concave Cutter Round Edge Cutter 175 Mm (7") Material is Carbon Steel, handmade by skilled worker from TianBonsai. Please choosing our tools safely, we offer the best Sales service. Normal usage within one year if the product is not up to standard, to ensure replacement, if your tools damaged by normal used, you just need to take a photo to us, a new item will immediately send to you without any expenses. Hardness is over HRC50. this grade tools also have nice quality and complete function The body of beginner bonsai tools be made by the intermediate technician, but the major function part were still made by the master craftsman from TianBonsai, E.G the cutter edge, so even be the beginner tools, you still can getting the nice user experienced when you use them.