Manufactured in the UK by Conservation Resources, these envelopes are made out of 120gsm sulphur and lignin free unbuffered paper. We use our neutral pH adhesives throughout. Envelopes are hand-made. This product opens along the short side. The paper  has passed the PAT test and is ideal for the storage of photographs, negatives or glass plates . Available in packs of 50. Bulk discounts available from 500 pieces.