Push Back
Push backs are often most commonly used with stud earrings. The earring back pushes straight right through the post of the earring making it very easy to use. It has a snug fit and it ensures your earrings stay in place.
Screw Back
Screw backs have a kind of winding groove on the post of the earring. One can twist the back around the post in multiple circular notions to tighten or loosen the earrings. This makes it difficult for the back to fall off on its own making it a more secure option.