C5 A5 size white ‘all board’ envelopes, 229x162mm. These envelopes contain board on both sides, providing extra protection for important documents, photo’s and items in the post. These high quality envelopes are 500mu in thickness and provide an excellent presentational look with a pure white finish. Classed by Royal Mail as ‘Large Letter’ size, and perfect for sending your documents through the post or via courier without them getting bent or creased.