Professional Ergo: features an ergonomic design with a high blade tension for straight accurate cuts (accepts 12" blade only). Alternative 55 degree blade mounting for flush cutting. Single touch spring loaded blade release mechanism for blade changes. Bi-metal blade included . CarboCut: features the Ultralight hacksaw frame with a Tungsten Carbide blade specifically for cutting carbon steerers. Ultralight: 11oz saw frame features 90° blade mounting, accepts both 10” and 12" blades. Bi-metal blade included.