C6 Black Gusset 180gsm Envelopes (Qty 200) 162mm x 114mm x 25mm1 2 day delivery as standard on this product These C6 Black Gusset Envelopes are made from high grade 180gsm paper, which is much thicker than your average envelope, meaning a real luxury feel with the added advantage of protecting the contents of the envelope too. The gusset feature these envelopes expand to allow more capacity means they are ideal for brochures and chunky documents that wouldn't fit in a standard envelope. At C6 size, these