C4 letter envelopes are used for packing and sending all kinds of documents or letters. They protect the parcel from damage and excitement. Their main advantages are their high durability and low price. They are equipped with a self-adhesive strip, under which there is a tape with glue - an extremely practical solution, which ensures quick and permanent closure and gives the right to tight and appropriate protection of the parcel. C4 envelopes are available in white and brown.