High carbon steel blade for maximum blade extension.Reads to 1/16" graduations.Long-lasting stainless steel spring for smooth operation.Sliding thumb lock and quick auto return.Sliding hook for inside and outside measurements.High-impact ABS case. ⚠ WARNING: This product can expose you to DEHP, which is known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.