Developed in partnership with Promixx, the Opti-Lock™ Shaker features a patented, single-direction sealing mechanism with an audible & tactile lid locking device that delivers leak-proof performance and unmistakable confidence in use. It's a tangible expression of Optimum Nutrition's commitment to quality, innovation, and consumer-first design.

Wash thoroughly before use.
For best results, add liquid before adding your powder.