Single Window #10 with #9 Return#10 mailing envelope that features a self-sealing flap. Simply press together to sealno moisture requiredOverall size: 9-1/2"W x 4-1/8"HWindow with clear film aligns with delivery address on invoiceWindow is 4-1/2"W x 1-1/8"H, positioned 7/8" from left edge and 1/2" from bottom edgePreinserted #9 gummed return envelope measures 8-7/8"W x 3-7/8"HSets are available in both white and blue stock