This double-concave glass lens is made of polished optical glass. It measures 50mm in diameter and has a focal length of 20cm.
PRODUCT WARNINGS
WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
Our products are not toys. Use in a laboratory or educational setting only. Not for children 13 and under.