CH Print Services Short run envelope printing services is part of the office printing range and is a brilliant way to establish and maintain a professional company brand image. We provide the ability to print across the flap, allowing your designs to create maximum impact. All our envelopes are laser guaranteed and available in a wide range of sizes, both windowed and non-windowed. All our envelopes are peel and seal. In our C5 & DL envelopes the flap is on the long edge and on our C4 envelopes the flap is on the short edge. We also offer C6 envelopes too.