Since developing the first disposable industrial marker, Diagraph has led the way with markers that perform on hard-to-mark surfaces and hold up under tough conditions.

GPX valve action markers are for hard-to-mark surfaces. GPX markers produce fast drying, opaque, permanent marks on metal wood, corrugated, rubber, plastic, glass porous and non-porous surfaces. GPX markers are available in 8 weather and fade-resistant colors

Markers are pre-packaged in cartons of a single color. Colors cannot be mixed within a carton.