Rotary die-cut envelopes involves cut through or sometimes crush creasing. It requires either Flexible Dies or Solid Rotary Dies according to different types of envelope converting machines. Flexible Dies are often be made with base pin holes or curved edges to work with specialized Magnetic Cylinder with pins. The outline shapes of envelopes can be die-cut by Solid Engraved Rotary Dies with Anvil Roller, the folding lines of envelopes can be done by Solid Rotary Dies working with hard Rubber Coated Rollers.