Our industrial turned contemporary open ended envelope with a great string and button closure. It is the standard business size for an 8 1/2" x 11" folded in thirds. In our perfect black with no hint of blue or brown. The US Post Office says that these envelopes need to be hand cancelled (a $0.12 surcharge). However, most branches seem just fine with them. To be perfectly safe, we recommend you bring them in to be hand cancelled and see if they charge you. Size - 4 1/8" x 9 1/2" Sold in packs of 10. When designing, remember that darker colors may rub off on lighter colors. Consider using a layer (such as tissue) between the different colors.