Fine tuning of shock piston sizes has always been a tuning tool for the pro's. Now with this new tool from Core RC its a simple task for any racer. This hand drill comes included with 8 different drill bits 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm and 1.8mm. 2 double ended chucks are included allowing for drill sizes between 0 to 2.9mm, for other simple hand drilling uses.