Staedtler Lumocolor 108 Permanent Glasochrom Pencils are waterproof wood-cased pencil in 6 colours. For opaque drawing and writing on almost all surfaces even on dark or transparent ones, e.g. paper, plastic, metal, glass, wood, leather and stone. No bleeding through paper. Wood from PEFC-certified, sustainably managed forests. Mars double-hole sharpener 510 25 or tub sharpener 512 002 for ideal sharpening results.