M55-S3. Zig Calligraphy Pen Square-Cut Set of 3. 3mm, 2mm, and 1mm.
The hard/stiff tips of these calligraphy markers make for crisp letters, and the tips stay sharp longer and won't mush up as fast as many other markers. Non-waterproof, dye ink. Black.
"I have been using the ZIG markers which you sent, and they work very well indeed! I even passed them around in my calligraphy courses to get the reaction from students, both beginners and experienced old hands at the matter. All found them terrific." --Kate Wolff