The difference between CYO rings and pre-designed rings is the whole process that goes into making them. For a CYO ring, you can customize every bit of your engagement ring. Right from selecting the setting in which your diamond will be held securely, to the diamond shape, and metal color that you want. However, a pre-designed engagement ring is a piece of jewelry that is already made when you place your order. To simply explain, these are the types of engagement rings in which you can pick a ring that is readily available to you. When you choose a pre-set engagement ring, the setting, diamond cut, and style are all pre-made, and all you have to do is choose the engagement ring that best suits your style. The best thing is that these rings are ready to ship to you.