What makes these marker pens good for deep holes?
These markers feature an extra-long 20mm nib (long nose) that can reach into deep holes, grooves, and tight spaces where standard markers can't, making them ideal for mechanical, welding, and construction marking.
Is the ink really waterproof and quick-drying?
Yes. The ink is formulated to be quick-drying and waterproof once set, resisting smudging from water, oils, and handling, which is essential for durable markings in workshops or on job sites.