Full Color Envelopes. #10 Envelopes printed in full-color on premium smooth finish 60LB - Bright White Paper. Custom-printed business envelopes are important business and advertising tools that often represent the first contact with a potential client. Every company correspondence mailed should leave a lasting impression of professionalism, which in turn inspires confidence. Your envelopes represent a great opportunity to reach new customers and reinforce your company message and brand. Size: 9.5 in. x 4.125 in. Turnaround: 8-9 business days.