This semi-circular refraction tank has a printed protractor on it to observe and measure refraction. Instructions included.
Sold in a pack of 10.
WARNING: This product can expose you to chemicals including styrene and lead, 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."