5 Star C5 Window Pocket Envelope Press Seal 100gsm White 229x162mm (Pack of 500) 5532585 Star white C5 pocket envelopes. These envelopes are made from mediumweight 100gsm 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. C5 size 229x162mm Made from mediumweight 100gsm paper Window size of 100x45mm Window position 60mm in from LHS, 24mm up Press seal closure meaning that