The five accessories come from three companies and break down into two categories. Belkin’s TuneBase FM with ClearScan ($90) and Macally’s BTCup ($100)—a more expensive sequel to its earlier FMCup—both combine an FM transmitter with an iPod car mount and car charger, but vary considerably from there. Kensington’s Liquid FM ($80), Liquid FM Plus ($70), and Liquid FM Deluxe ($100) are cables that offer only the FM transmitter…
