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 Window (1 1/8 x 4 3/4, 3/4L - 1/2B)White Sulphite (SFI CERTIFIED) 92% Brightness Vellum Finish Diagonal Seams Poly Window Remoistening Seal Flap Down