Skullcandy is hitting CES with a characteristically bold claim: its new Fix in-ear headphones are touted as the first to never fall out of your ears, irrespective of the intensity of your physical activity. We've matched them up against the Yurbuds Ironman Series, a rather larger pair of in-ear speakers, which makes the exact same assertion. Both companies have patented their particular technology and both claim to be the one and only true solution. Obviously targeting runners, vigorous exercisers and discreet headbangers, they're priced at $70 for Skullcandy's Fix and $50 for the Yurbuds Ironmans. We've had a pair of each to play around with for a few hours here and sound quality is generally satisfactory on both. The Ironmans are much punchier in the bass range and offer significantly better sound isolation -- a lot of external noise leaks in through the Fix's seal, but the oversized Ironman buds netralize the vast majority of it. Both sets feel comfortable in the ear and shouldn't cause any grief if you opt to wear them for prolonged jogs outdoors ... or impromptu indoor moshing sessions.