Fine-tuning shock piston sizes has always been a tuning tool for professionals. Now, with this new Core RC tool, it's an easy task for any racer. This hand drill comes included with 8 different bits of 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, and 1.8mm. Two double-ended chucks are included allowing drill sizes between 0 and 2.9mm for other simple hand-drilling uses.