48X Tracer Pencil Refills Black 2.8mm for Carpenter Solid Deep Hole Mark Pencil
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. 48 Pcs Tracer Pencil Refill 2.8mm Solid Carpenter Pencil Deep Hole Marker Refill.