Radnor Metal Ball Point Markers feature durable aluminum tubes with non-clogging, tough, case-hardened steel points and precision 440 stainless steel balls. These handy markers utilize a specially formulated polyurethane paint and will write in any position: horizontal, vertical and overhead. Marks are fast drying. Metal Markers are available in a tube or handy, refillable, unbreakable plastic bottle. Marks on all metals, wood, rubber, glass, etc. Marks on rough, smooth, wet, oily or dry surfaces. Marks withstand heat and weathering and won't chip, peel, fade or rub off. Radnor Markers are manufactured by J. P. Nissen, a leading supplier of markers to industry. All markers are guaranteed for the life of the product.