4 flap envelopes, in white acid-free paper, 90grs / m2, pH 6.8-7.0.
 They protect photographs and negatives from mechanical damage and due to inadequate environmental conditions.
 Available in various formats: 6x9cm, 9x12cm, 10x13cm, 12.2x16.5cm, 13x18cm, 18x24cm, 24x30cm.
 Sold in packs of 100 units
 The role passed the PAT (Photo Activity Test), from the Image Permanence Institute (Rochester USA).