These Ryman Envelopes are C5 sized, 90gsm and come in a pack of 50.These envelopes feature a peel and seal closure making them easy to use and more hygienic than standard gummed envelopes and are ideal for sending A5 documents as well as sending folded A4 documents. They have a blue obscuring pattern inside so that the contents does not appear visible from the outside. They would be classed as a small letter when it comes to postal charges.These C5 Ryman Envelopes are a must have for any office, school or university and are also ideal for use at home.