Western Sulphite® Commercial Window - This popular line of white wove commercial window envelopes is manufactured with diagonal seams, poly window and a traditional remoistening seal.Western Sulphite SFI "#1" Window (1 1/4 x 4, 5/8L - 13/16B)White Sulphite (SFI CERTIFIED)92% Brightness Vellum Finish Diagonal Seams Poly Window Remoistening Seal Flap Down