Fixed position splitters mean the point where the helmet straps divide below your ears is set in place and can't be moved up or down. This design is common on some aero road helmets and urban commuting helmets because it creates a cleaner, more streamlined look with less strap clutter.
The trade-off is fit customization. Since the splitters don't adjust, the straps may not sit perfectly below your earlobes on every head shape. If your ears sit higher or lower than average, the straps could rub or feel awkward. For most riders, fixed splitters work fine and make fitting simpler—just buckle and go.
If you've had trouble with straps creeping or chafing in the past, or you know you're picky about strap positioning, you might prefer adjustable splitters with locking instead. But if you want a clean look and easy setup for casual or aero riding, fixed splitters are a solid choice.