J257 Refractometer offers full and Traceable Calibration The Rudolph J257 Refractometer offers 1 pt, 2 pt, or a full multi-point calibration.

Designed as a research quality instrument the Rudolph J357 Automatic Digital Refractometer offers one of the highest measurement ranges of any instrument in the Rudolph refractometer product line.

DESIGNED FOR - testing the concentration of saltwater, help you to monitor and control the concentration of salt water. WIDELY USE - Can be used for Aquariums, Marine Monitoring, Agricultural ...