Large PCB tungsten steel (tungsten carbide) drill bits generally refer to the upper size limit of micro-drill kits, spanning from 1.5mm up to 3.175mm (1/8 inch) with a uniform 3.175mm shank size designed for CNC routers and precision rotary tools.

Material: Solid tungsten carbide, offering extreme rigidity and wear resistance compared to standard high-speed steel (HSS).
Shank Size: Standardized at 3.175mm (1/8") to fit Dremel, CNC engraving, and PCB drilling machines.
Size Range for "Large" Bits: Typically 1.5mm to 3.175mm, used for mounting holes, board edges, or larger-diameter terminal passthroughs.
Flute Design: Spiral flutes that clear chips efficiently out of fiberglass (FR4), plastics, and copper composites

Case of 10.

Size: Large.