Answer Question
A helmet light should be at least 700 lumens to get good night vision while mountain biking on single track. So a good light for the Troy Lee A1 or A2 helmets that isn't too expensive would be the NiteRider Lumina 750 Boost light, along with the NiteRider Lumina Helmet Mount Strap.
For a bit more brightness on the trail go with the NiteRider Lumina 950 Boost light.
In addition to this, pair your helmet light up with a handle bar light like the NiteRider Lumina Micro 600 Bike Light for the great night vision riding.
What are some of the best full face DH mountain biking helmets?
What is the best mountain bike trail pump?
Does Oakley make mountain bike goggles?
What does it cost to ship a Mountain Bike?
What is the Best Digital Bike Tire Pressure Gauge?
How can I secure my bike in my garage so it can't be stolen?
What are the Best Cycling Sunglasses?
What is the best single bike hitch mount rack?