As Trustic's most versatile and economic marker, the original Trustic Crayon marker combines the durability of wax in the convenience of a crayon. The real crayon formula has superior marking performance on oily, icy, wet, dry or cold surfaces and is weather- and UV-resistant. This excellent marker works on rough, rusty, smooth, or dirty surfaces, such as wood, ceramics, glass, metal, rubber, carton, plastic and even underwater.