These are printed on either White Premium Opaque - 70lb, White Linen Uncoated - 70lb, and Also Self Seal Security Strip Uncoated - 60lb paper stock and which is the premium ones that are helpful #10 envelope printing from PrintMagic and easy. The Self Seal that comes with a gummed flap to avoid licking or applying any glue to secure your envelope flap. If you are looking for a different type of flap option then you can fill up the custom quote form for the customized envelopes or call us on +1-888.391-0199.