• What frame material is right for me?

It depends on what features you are looking for. The following categories can help with your decision:
Weight: If you want a super light frame, go with one that's 15 grams or lower. Titanium frames are generally very light.
Material: You have the choice between metal or plastic. Metal tends to be lighter. Plastic frames tend to be more durable.
Flexibility: This is a nice feature to have for kids or sports glasses. We have a line of kids plastic flexible frames that are forgiving and durable.
Color: Plastic frames tend to come in more color options, especially acetate plastic.
Hypoallergenic: Stainless steel, titanium and acetate frames are hypoallergenic.

• What do the numbers printed on my frame mean? (please keep the images on the bottom of the answer)

Non-Zenni frames: Some frames have a series of numbers printed on the inside of a temple arm (the part that goes behind your ear). The first numbers are typically the manufacturer’s style number and a color code. But farther down the temple arm, there may be important numbers that refer to the dimensions of the frame. These numbers are the measurement, in millimeters, of the lens width, nose bridge width, and temple arm length. Often the lens width and nose bridge width are 2-digit numbers separated by a square, and a temple arm length is a 3-digit number in front of or behind the others. Knowing these numbers can help you choose a frame similar in size when shopping.
Zenni Frames: You will find a frame number that consists of 6 or more numbers which will help you locate the frame on the Zenni website.