Embroidered Logos: Best Artwork Format?

What's the best artwork file format to send to your embroiderer?  Usually the format with the highest resolution works best.  High resolution files such as ai, eps and cdr files contain more detailed information so they make it easier for your decorator to create your embroidered design in less time. Not sure which file has the highest resolution?  Send what you have and let your decorator choose whats best.  Concerned about sending files you can't open?  Include a file that you can view such as a jpeg and mention that this is the correct design so your decorator knows what you want.