These envelopes are a UK made product and are the right choice when you want to make a real impression with your latest project. More sizes and colours available. Envelope packs from Craft UK. Great value pack of 30. Ideal for your handmade greetings cards - 100 gsm. C5 envelopes measure 6.4" x 9" - perfectly sized for A5 cards (an A4 sheet folded in half).