I was looking for a way to better utilize my Mp3 capabilites on my Blackberry Curve. I can across this audio cable at Walmart and it turned out to be just perfect. It's a 3.5 mm audio actually designed for use in plugging up a iPod to your car stereo. I figured since the jack on my Blackberry was the same size I would pick it up, and I'm glad I did! It's given me even more use out of my phone than before. With this Belkin audio cable attached to my Blackberry, I can not only hear the audio over the car speakers from my mp3's stored on it, I can also hear the turn by turn directions when I use my GPS, as well as using it as a hands free device by plugging it in and using the speaker phone option. The 6 foot length of the cable is perfect for my needs too, rolled up, it's just the right size for storing in the dash compartment and doesn't take up much space. I love it when a product like this can open up a lot of possibilities, allowing me to get more use out of the devices I use on a regular basis. So if you have a smart phone with a jack like this and a jack for a iPod connection in your vehicle, grab one of these, you'll be glad you did!