What is the Optimum Nutrition Gainer Shaker? The Optimum Nutrition Gainer Shaker is a high-capacity, 1-litre shaker, designed for Serious Mass users who need a durable, leak-proof solution for mixing large, high-calorie shakes with ease. Benefits: 1-litre capacity – Perfect for mixing serious-sized shakes. Stainless steel wire mixing ball – Ensures smooth, lump-free shakes. Leak-proof, screw-top lid – Secure and mess-free on the go. BPA & DEHP free – Made from high-quality, safe materials. When to Use This Product: Post-Workout – Mix and enjoy your gainer shake. Between Meals – Convenient for high-calorie nutrition on the go. Anytime You Need a Big Shake – Designed for Serious Mass users. Why Choose This Product? With a sleek Jet Black design, Optimum Nutrition branding, and a secure, easy-to-use flip-top cap, the Gainer Shaker is the ultimate tool for mixing large, high-calorie shakes—with no mess, no hassle.