A set of 2 rulers, in portrait and landscape A5 size
For ruling repetitive guidelines of 2.5mm, 3mm, 4mm, 6mm quickly in 1:1 and 2:1 ratio.
Can draw slant line of 35°, 45°, 52°, 55°, 65°, 75°, 85° for different scripts including Copperplate, Spencerian, Gothic and Italic, etc.
Center Envelope Guidelines for A, C, and DL Types.
 
Other rulers from 21Lines
X-Ruler (for 3:2 ratio) here
Lettering Grid Ruler here