If you have an iPod with color display and 20/30GB, then you will want Apple's MA122G/A iPod Universal Dock Adapter 3-pack. This Dock Adapter helps your iPod fit right into the iPod Universal Dock and other products that use the Universal Dock system. This particular model is compatible with the 20 or 30 gig iPod with color display.
When you want to connect a different-size iPod, simply select another Dock Adapter and insert your new iPod. Each package includes three Dock Adapters so you can select the adapter that fits your particular iPod model.
Versatility
With this three pack of dock adapters you can fit your iPod to the iPod Universal Dock and other products that use the Universal Dock system. Simply insert the adapter for your model into the dock and then plug in your iPod.