The best bottle to use for mixing drinks a must for rego build and rego rapid due to the whey protein this bottle is specially made for sis with handy markings that are a key part of the easy mix system to 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 water the result is no fuss no mess and less chance of contaminating yourdrink assuming that you keep