6-54x Tracer Pencil Refills Scriber Deep Hole Pen Lead Solid Carpenter Set 2.8mm
They work great for deep-hole marking, allows it to draw in holes that other oil-based pencils cannot, so it will be a good refill for your work. 6-54X Tracer Pencil Refill 2.8mm Solid Carpenter Pencil Deep Hole Marker Refill.