#10 - SFI Postage Meter Window (1 1/8 x 4 3/4, 4 Left - 2 1/2Bottom) 24#Postage Meter Window Envelope - Manufactured with diagonal seams, poly window and a traditional remoistening seal, this envelope - with its unique "upside down" window position - is made to be used on certain postage meter equipment.White Sulphite (SFI CERTIFIED)92% Brightness Vellum Finish Diagonal Seams Poly Window Remoistening SealFlap Down