This can be used with any device that has a headphone jack. My daughter plugs her iPod into it in the car. But your vehicle has to have an auxiliary jack also.
I'm sure as long as the kindle has a regular headphone jack, this cable should be compatible with the kindle and whatever sound system you are plugging it into.
This is an auxiliary cable. You plug one end into your iPhone where you would normally plug in the headphones. The other end has the same type of connection. We plug into the car to listen to iPhone through speakers without using the blue tooth
There is a iPhone bundle in stock, it has a iPhone cover, the jack adapter and earbuds, which is on sale at this time. Model # 910077, SKU # 1310752191.
If your iPhone has a 3.5 mm jack, then yes this will work with your iPhone. I don't know which model you have so I can't tell you which connector you would need. Best Buy will have any cable that your phone can use.