It’s a Birthday so it’s time to party! Get the cake, balloons and your best ones to celebrate. Details: Designed by: Marisu Valencia. Size A6 (105 x 148mm / 4.1 x 5.8 inches). - that fits as a standard sized letter in the UK mail. Produced from sustainable forests and/or recycled materials. Blank inside for your own message. 100% Recycled Kraft Paper Envelope. Made in the UK.