Precision Leather Scribing Gauge - Mercury Marking Tool with Locking Needle, Sharp Engraver for Clean Lines on Leathercraft & DIY. A beautifully designed scribing system is light and compact, and you can use a needle to accurately mark the line with one hand. You can also clamp the copper tube mercury refill and clearly mark the chrome tanned leather. Stable and sharp marks are used to make sure the structure is suitable for precise operation.