Essential Oil Keys are essential tools for opening and closing essential oil bottles. - No more sore fingers from trying to wiggle orifice reducers or roller balls. - No more broken roller balls. -This means you can stop trying to use knives, teeth or corkscrews. Easily pry off a standard 5/8 inch diameter orifice reducer or a standard 1/2 inch diameter roller ball, just insert and press down using countersunk half circle on the “Standard Key”. Easily embed a standard 1/2 inch diameter roller ball, just press down on the outside of the ball using the circle on the “Standard Key”. The “Standard Key” is used for standard sized essential oil bottles. It does not open & close smaller bottles like the “Sample Key” and “Cheese Key” do. But it is even easier to use than the “Cheese Key” because there is more surface area of the key available to grip when pressing down.