Smooth white, All Board Envelopes, measuring 330mm x 457mm they are C3 size so fit A3 documents. Built out of premium grade 500 micron, 350gsm, GD2 fully coated chipboard, they are incredibly robust and fast to use. A key feature of these board envelopes is their time-saving qualities - they are quick and easy to seal, simply secure a pre-folded flap with its peel and seal strip. They also have a peel-open strip build in, which means the receiver can open the envelope quickly too. Their coated surface can be printed on, and self-adhesive labels stick fast. Choose them to protect paper, card and thin items during transit.