The Mitutoyo ABSOLUTE 500 series caliper with exclusive AOS sensor technology is a Digimatic caliper that is made of durable hardened stainless steel and uses Mitutoyo’s ABSOLUTE linear encoder technology, which allows you to “set and forget” the origin and measure in awkward or difficult locations. This series also utilizes the patented Advanced Onsite Sensor (AOS) offering improved measurement dependability by increasing resistance to harsh workshop conditions.