Sennheiser and Adidas have teamed up to introduce a new lineup of sport headphones developed and designed for use with the iPhone. The lineup includes that CX 680i Sports, an in-ear model that sells for $120, the MX 680i Sports, a set of traditional sport earbuds that sell for $80, the OMX 680i Sports, an ear-clip model that sells for $80, and the PMX 680i Sports, a neckband sports headset that also retails for $80. All four models feature sweat-…
