These drills are intended for use in the fine cutting or trimming of thin (less than 1.0 mm) hard and semi-hard thermoformed appliances (produced from materials such as Erkodur, Erkolen, and Erkoflex-bleach). They are standalone replacement drills identical to those included with the Erkodent Trimming and Polishing Kit. Use with caution at high revolutions (20,000 – 40,000 rpm), applying only light pressure. Always wear protective eyewear during use.