These chalk markers are for use on smooth surfaces such as glass, plastics, chalk boards, mirrors, ceramics and more. With three different tip sizes, this set will be useful for any application, and it is easily erasable while still wet.Details: White 3 tip shapes (fine, chisel and wide) 6 packs (3 markers per pack, 18 total markers) Water-based pigment ink Highly opaque Lightfast, odorless and xylene free Instructions on back of packageCAUTION: Keep away from flames, even when empty.