








O'Neal - Sierra II Flat Helmet
O'Neal - Sierra II Flat Helmet
The O'Neal Sierra II Flat Helmet feels like that dependable lid you grab every weekend, light, well-vented, and ready for whatever track or trail you throw at it.
Balanced shell weight, efficient venting, and a plush liner that keeps its shape moto after moto.
Why We Like It:
Everything about it feels dialed: airflow, comfort, and control without unnecessary extras.
Why It’ll Work for You:
If you want straightforward performance, easy goggle fit, and comfort that holds up, this helmet just works.
Variants / Options:
Available in several colorways and sizes for a dialed-in fit.
Key Features:
Lightweight, balanced shell design
Airflow channels for active cooling
Moisture-wicking comfort liner
Wide goggle port and adjustable peak
Shell in constructed with ABS
Weight: 1590g (± 50g)
Moisture wicking, removable/washable air channeled comfort liner
Vent holes for optimal ventilation
Integrated face shield
Height adjustable helmet shield
Padded Chin Strap with Double-D safety lock
Meets DOT and ECE 22.05 safety standards
Designed for Street, Enduro, Side by Side and Adventure Bike’s
Replacement parts available
Original: $161.99
-70%$161.99
$48.60Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
O'Neal - Sierra II Flat Helmet
The O'Neal Sierra II Flat Helmet feels like that dependable lid you grab every weekend, light, well-vented, and ready for whatever track or trail you throw at it.
Balanced shell weight, efficient venting, and a plush liner that keeps its shape moto after moto.
Why We Like It:
Everything about it feels dialed: airflow, comfort, and control without unnecessary extras.
Why It’ll Work for You:
If you want straightforward performance, easy goggle fit, and comfort that holds up, this helmet just works.
Variants / Options:
Available in several colorways and sizes for a dialed-in fit.
Key Features:
Lightweight, balanced shell design
Airflow channels for active cooling
Moisture-wicking comfort liner
Wide goggle port and adjustable peak
Shell in constructed with ABS
Weight: 1590g (± 50g)
Moisture wicking, removable/washable air channeled comfort liner
Vent holes for optimal ventilation
Integrated face shield
Height adjustable helmet shield
Padded Chin Strap with Double-D safety lock
Meets DOT and ECE 22.05 safety standards
Designed for Street, Enduro, Side by Side and Adventure Bike’s
Replacement parts available























