Manufactured to very tight tolerances. Tungsten carabiners with silver tips give them the strength and durability you need to get the job done. Normally I'd unscientifically inspect them like heads, but since these are precision cutters, a hit of a sledgehammer can simply push them out of required tolerances, requiring them to be manually inspected for quality before cutting. Parts and pieces are well matched, and clearances and tolerances are the same for the entire blade set. Sizes are engraved on each cutting plotter for reference. The groves ensure that the flow of garbage gently moves away from what is being cut down. Supplied with two guide pins as well as a rubber-like casing to keep each one separate so they don't bump into each other in transit. As for durability, time will tell so if an upgrade is needed I'll quickly say a few words, but so far I'm pleased with the quality and functionality of the thirteen piece set. Four stars โญ๏ธโญ๏ธโญ๏ธโญ๏ธ!