This pack of 2 POSCA Marker Pens features an ultra-fine, precise calibrated tip to produce refined lines which are 0.7 to 1mm wide with a water based ink which produces no odour. If used on porous surfaces such as paper, cardboard, stone, wood, silicone, fabric or unglazed ceramic, these pens are permanent.Smooth surfaces such as glass, glazed ceramics, PVC and smooth metal means your design will need fixing with a spray of water based varnish, apart from glass which should be put in a 160 degree oven for 45 minutes beforehand.Instructions on how to make permanent:- Terracotta - by baking at 220 degrees for 45 minutes, then spraying with clear varnish- Porcelain - by baking at 160 degrees for 45 minutes, then spraying with clear varnish- Glass - by baking in the oven at 160 degrees for 45 minutes then spraying with clear varnish- Textiles - by ironing on reverse- Metal, plastic and wood - by spraying with clear varnish. Precise, calibrated tip produces refined lines. Extra-fine 0.7-1mm line width. Will write on almost any surface . Water based. Permanent on porous surfaces. Erasable on smooth surfaces. Bleed-proof on paper and card. Pack of 2. Approximate dimensions (mm) H 275 W 200 D 8