These envelopes are made of paper specially designed to enhance the feel and performance of fountain pens. The paper is extremely smooth, bleed-resistant and feather-resistant. In addition, both the front and back sides of the envelopes are lined. The envelopes are "Western style," which means that the envelope opening is along the long dimension of the envelope.
Also pictured: Pilot Iroshizuku Ink - Kon-peki, Pilot Prera Fountain Pen - Ivory Body, and Pilot Letter Pad