These Basildon Bond Envelopes are 90gsm and come in a pack of 20.These envelopes are 89x187mm, made from high quality paper and feature a distinctive watermark adding a touch of style. They are gummed and can be used with size 3 Basildon Bond writing paper.These Basildon Bond Envelopes are perfect for personal and business users who want to add a touch of class to their correspondence.. P4TO (89x187mm) Envelopes. 20 Pack Quality Paper: High quality 90gsm Watermarked White Envelopes . Peal & Seal Envelopes: Allowing the envelopes to be securely closed