Speed Increasing Handpiece 1:5 with External Spray For Drills 1.6 mm This is ideal for matching with the Satelec Cocoon Spray - allowing drilling speeds up to 200,000rpm (getting in to turbine speed territory but run from a reliable micromotor). The external water source will allow cooling at the drill tip to eliminate any build up of heat and tooth trauma. HANDY TIP - Always follow oiling procedures for these handpieces to ensure longevity of the handpiece, note: running without oiling even briefly may damage the handpiece and nullify the warranty.