Western Sulphite® Neopost Machine Insertable Window Envelope - This envelope has been tested on Neopost inserting equipment, running well and meeting specifications. It is manufactured with diagonal seams, poly window and a traditional remoistening seal.Western Sulphite SFI Neopost Machine Insertable "C" Window (1 1/8 x 4 1/2, 7/8L - 1/2B)White Sulphite (SFI CERTIFIED) 92% Brightness Vellum FinishDiagonal Seams Poly Window Remoistening Seal Flap Down