or on your keychain

refillable top-cap eraser

canvas or even wood

even ink flow rather than the dry skipping that can occur with wide felt-tip markers at this scale

or surface breakdown under repeated erasing

leuchtturm1917 notebook a5 soft cover squared Saeio or on your keychainFormat: A5 (145 x 210 mm) 123 pages 5 x 5 mm squared grid 80 g m ink proof, acid free Binding: Flexible softcover thread bound 180 flat lay Includes: Table of contents, 8 perforated sheets, 2 ribbon markers, elastic band, expandable rear pocket, archival stickers A lightweight 5 x 5 mm graph grid notebook for software engineers, architects, researchers, and technical designers who need precise geometric structure without the weight of a hardcover. The