The best bottle to use for mixing drinks a must for Rego Build and Rego Rapid due to the whey proteinThis bottle is specially made for SiS with handy markings that are a key part of the easy-mix systemTo use start by adding drink powder up to the appropriate level as marked on the bottle; then part fill with water and shake to mix the drink; finally top up to the final level with more waterThe result is no fuss no mess and less chance of contaminating yourdrink - assuming that you keep your bottle clean!An huge opening makes it the easiest mixing bottle yet to pour in powder from large tubs