Determine what you need based on what is currently on your door. Weather strip varies within door models, so there is not one specific type that works with each model. Remove a portion of the existing seal from the garage door to see the size and shape of the ends going into the track.  The only important factor when determining the correct one is the shape and size of the ends going into the track grooves on the bottom bracket of your door.

View instructions on how to remove and replace weather seal here

We carry the two most common types below. If you aren't sure you can order a sample pack here to try - Weather Seal Sample Pack

Ends are approximately 3/16" and slightly rounded

Ends are approximately 5/16" and flat like a T

Items include weatherstrip ONLY - Diagram shows side view of gasket with weather seal installed for demonstration only.