Stream II Solid Full Face Motorcycle Helmet
It’s hard to imagine just how good the LS2 Stream II full-face motorcycle helmet is. Style, features and performance that surpass helmets costing literally twice the price, this helmet is... Read More
It’s hard to imagine just how good the LS2 Stream II full-face motorcycle helmet is. Style, features and performance that surpass helmets costing literally twice the price, this helmet is an out-of-the-park home run. It starts with an aerodynamic, sport styled shell made from LS2’s proprietary Kinetic Polymer Alloy (KPA). This high-tech material uses nanotechnology to blend microscopic aramid fibers with a high-end polymer. This blend allows for amazing energy managing performance with managed flexibility that absorbs energy without the ricochet effect of inferior materials. The Stream II meets the ECE 22.06 rotational energy management specifications using Advanced Rotational Energy Management Technology (AREM), another LS2 proprietary process. The rear spoiler allows for dynamic flow-through ventilation. The 3D laser cut foam in the cheek pads, removeable, washable liner with special flex-crown comfort system is super comfortable and easy to keep fresh. 3 shells and 5 energy absorbing EPS liners make for a fit that is nothing short of amazing. The optically correct, Class A polycarbonate shield is Pinlock ready, for the ultimate in fog management (Pinlock sold separately). The overall finish and performance sets the Stream II at the forefront of full-face motorcycle helmets. Even those costing twice the price. Meets or exceeds ECE 22.06 and DOT FMVSS standards. Intermediate oval fit.
- High tech, aerodynamic, sport styled Kinetic Polymer Alloy shell
- AREM rotational energy management meets ECE 22.06 standards
- Dynamic, flow-through ventilation
- Quick release chin strap
How to measure
Measure the circumference of your head with a tape measure, starting above the ear, circling completely around about half an inch above the eyebrows and across the fullest part of the back of the head. Measure several times for accuracy. If you fall between two sizes, choose the larger; the helmet should be as snug as possible without causing pain.
LS2 Helmets size chart
| Size | Head circumference (cm) | Head circumference (inches) |
|---|---|---|
| XS | 53-54 | 20 7/8 - 21 1/4 |
| S | 55-56 | 21 5/8 - 22 |
| M | 57-58 | 22 1/2 - 22 7/8 |
| L | 59-60 | 23 1/4 - 23 5/8 |
| XL | 61-62 | 24 - 24 3/8 |
| 2XL | 63-64 | 24 3/4 - 25 1/4 |
| 3XL | 65-66 | 25 5/8 - 26 |
| 4XL | 67-68 | 26 3/8 - 26 3/4 |
Youth sizes
| Chart | Size | Head circumference (cm) | Head circumference (inches) |
|---|---|---|---|
| Rapid Mini (kids street full-face) | S | 47-48 | 18 1/2 - 19 |
| Rapid Mini (kids street full-face) | M | 49-50 | 19 1/2 - 19 3/4 |
| Rapid Mini (kids street full-face) | L | 51-52 | 20 - 20 1/2 |
| Gate Youth (youth MX) | S | 51-52 | 20 - 20 1/2 |
| Gate Youth (youth MX) | M | 53-54 | 20 7/8 - 21 1/4 |
| Gate Youth (youth MX) | L | 55-56 | 21 5/8 - 22 |
One official LS2 USA adult chart (XS-4XL) for all adult models; different head shapes may need a size up/down in a given model, and models use multiple shell sizes. Two model-specific youth charts (Rapid Mini street, Gate Youth MX) — they differ, use the right one per model.
Manufacturer sizing data · verified July 8, 2026
