You're going to LOVE the fit. Try it on and experience our perfect fit. If you don't love it, send it back in new and unused condition within 30 days for an exchange or full refund*. Risk free.
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Sacrifice nothing with our highest performance snowmobile helmet ever. The 509 Altitude 2.0 Pro Carbon Fiber 3K Helmet boasts every advantage for the most demanding off-trail riders. 3K carbon composite construction makes it lighter, stronger, and sleeker than anything else in the lineup. For those who run at redline, the helmet maximizes airflow with open upper and rear vents plus a 40% larger chinbar intake. It also features the MIPS Brain Protection System for the highest levels of safety.
Key Features
- Pro MIPS® Brain Protection System for ultimate safety → Learn More
- Hand Lay-up Carbon Fiber 3K Shell – Ultimate protection in a lightweight option
- Upper vents with on/off shutter closure for airflow control
- Nine intake vents and four exhaust vents for optimal airflow
- Fidlock® The Fidlock System is a cutting-edge magnetic chinstrap buckle used in motorsport helmets ensuring quick, secure, closures with one hand and is DOT and ECE compliant.chinstrap strap closure for easy in and out
- Pro-Series Breathbox included
- Replaceable polycarbonate visor with Read More
Size Guide
Not sure about your size? Try on at your local dealer!
*Street Helmets are a tighter fit due to cheekpad compression, however, they do pack out over time/use.
How to Measure
When measuring your head, use a cloth tape. Start it just above your eyebrows and circle it around the thickest point in the rear of your head and then reference the size guide below.
Scroll to the right to see more sizes
| Size | US Hat Size | Inches | Centimeters |
| X-Small | 6 5/8 - 6 3/4 | 20 7/8 - 21 1/8 | 53 - 54 |
| Small | 6 7/8 - 7 | 21 5/8 - 21 7/8 | 55 - 56 |
| Medium | 7 1/8 - 7 1/4 | 22 1/2 - 22 5/8 | 57 - 58 |
| Large | 7 3/8 - 7 1/2 | 23 1/4 - 23 1/2 | 59 - 60 |
| X-Large | 7 5/8 - 7 3/4 | 24 - 24 1/4 | 61 - 62 |
| 2X-Large | 8 | 24 3/4 - 25 | 63 - 64 |
| 3X-Large | 8 3/4 | 25 1/4 - 25 3/4 | 64 - 65 |
| 4X-Large | 9 | 26 - 26 1/4 | 66 - 67 |
| Youth Small | 6 | 18 1/8 - 18 7/8 | 47 - 48 |
| Youth Medium | 6 1/8 - 6 1/4 | 19 1/4 - 19 5/8 | 49 - 50 |
| Youth Large | 6 3/8 - 6 1/2 | 20 - 20 1/2 | 51 - 52 |
Pressure Points
When trying on a helmet, take note of any pressure points on your forehead—a sign that the helmet is too round. Pressure points on the sides of your head indicate a helmet is too oval for the shape of your head. After you buy a new helmet, try wearing it for 30 to 45 minutes to check for pressure points before using it on a ride.
Pressure Points
When trying on a helmet, take note of any pressure points on your forehead—a sign that the helmet is too round. Pressure points on the sides of your head indicate a helmet is too oval for the shape of your head. After you buy a new helmet, try wearing it for 30 to 45 minutes to check for pressure points before using it on a ride.
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