Review (5/5): This is a terrific machine!
It's powerful and as accurate as you are experienced at using these types of machines. There is no printed manual with this but they do send you an email manual which is helpful. To open the slot, twist the blue section to the left and insert the selected tip and then twist it back to the right to secure the tip tightly. If you are having trouble with the tip not moving properly, twist the bottom completely off and look inside, make sure the hard, white plastic, protruding tip is sitting straight and twist the bottom on again. Turn it on and try again, it should give you a powerful spin. Be careful with the speed and how long you stay in one spot or it can burn you right through your nail. I read hundreds of reviews on many different machines and over all this was the best for the money. You will be happy with this product.