[Deep Hole Marking] The total length of this multi-purpose deep hole marker is approximately 138mm (5.43 inches). It can access hard-to-reach areas, making it ideal for marking through holes or other narrow spaces. Easy to use and portable. [Fast Drying and Waterproof] The ink dries quickly after application, preventing smudging from hands or fabric. The mark is waterproof and resistant to removal when submerged, suitable for outdoor use. [Material] This deep hole marker features a plastic body and carbon fiber tip, designed for durability and long service life. The pen has a slender design with a fine round tip. It contains permanent, waterproof ink that is fast-drying, xylene-free, and odorless. [Package Content] You will receive 10 marking pens: 3 blue, 3 red, 2 black, and 2 white. Multiple colors allow for color-coded markings and visibility on dark surfaces. Ideal for sharing and replacements. [Wide Application] Suitable for various surfaces including metal, plastic, glass, wood, and paper. Commonly used in furniture decoration, hardware processing, automotive manufacturing, shelving, lamp drilling positions, and industrial applications. Color: As shown Material: Plastic Package Contents: 10 x Marking Pen Note: Light reflection and different display settings may cause slight variations in the color shown. Measurement may vary by +/- 1-3cm.