5 Star C4 Window Pocket Envelope Press Seal 90gsm324x229mm White (Pack of 250) 6385665 Star white C4 pocket envelopes. These envelopes are made from lightweight 90gsm paper and feature a window, allowing you to clearly display the address of your correspondent. They feature a press seal, meaning that all you have to do is apply the two glued flaps together to form an instant bond. C4 size 324x229mm Made from lightweight 90gsm paper Press seal closure meaning that all you have to do is apply the two glued flaps together to form an