I have an EVS
neck collar which is the basically the same thing. I wear it all the time, even when it's over 100 degrees, whether I'm trail riding or MX'ng. My wife and I both got one after she broke her collarbone. The collar is suppose to help prevent your helmet
from hitting your collarbone and breaking it. It also limits the amount of movement for your neck in the event of a crash. My personal experience was coming off a 4th gear downhill double at Hangtown. Another rider had fallen and left his bike on the track. I didn't see it till I was already in the air and when I landed on it the bikes tangled and kicked me off over the bars. I'm not sure how fast I was going when I hit the dirt, but it was fast enough to break both my wrists and total my Bell Moto 7 helmet. I feel if I didn't have it on I would have wound up with atleast a broken collarbone. Once you start wearing one, you get use to it and will feel naked without it. My advice would be for everyone who falls, to get one and get use to wearing it. I don't even notice mine anymore and if it will help prevent injuries in a crash, I'll wear it. Dress for the crash, not the ride since crashing is a part of riding.