M5x0.9 is a rarely used thread size and it is almost impossible to find replacement screws with this thread. With this stamp you can make your own. Irwin/Hanson is a good brand that lives up to its name with this matrix. This is a 5/8" hex wrench, which is also rarely used, but if you don't have a 5/8" die, you can use a 5/8" wrench. Careful.