Good protection for mountain biking.
583670
Does protect the Iwatch very well but the seal will not let water escape after swimming. So you have dismantle it if the water drop freezes on the watch face.
2970151
These work very well for mountain biking, especially on cloudy days of riding! I would buy again.
2430008
It can use and have a good protection to ride short distances when the weather is cold but not freezen.
4416006
Very good combination of comfort while not begin too bulky to be a good solution for a mountain bike.
The ventilation system is a nice on hot days.
Wish it had more flexibility to move it forward and backward, as my previous seat had.
645686
I bought these for mountain biking. I wear them over merino wool boxer briefs and it's a great combo. These have just enough stretch, an athletic fit (I'm 6'1, 210, 35 waist and the large is perfect), dry quickly, and aren't too slippery. The elastic waist is good for sporting activities and the extra cargo pocket is very helpful. Plus, these are really cheap.
1244057
I contacted the company with my bike's measurements to make sure I got the correct size (I have a windscreen).

The good fit and elastic at the bottom means that the cover doesn't blow loose in the wind, and doesn't require straps.

I've owned this for a year, but I only use it in winter so I can't speak to its sun resistance.
4330176
I use this for skiing and cold, rainy or winter mountain biking. Good all purpose outdoor shell for a variety of activity and weather situations. Combined with a windproof fleece and wicking base layer, it gives me complete protection from the elements in the dead of winter. One thing to keep in mind is that it sizes a bit narrow. I ordered a size up to XL and it just fits with the additional layers.
1118156
Well made bike cover.  I like that the base of the grey part has some elastic on it so it cinches itself around the bike wheels well.  I also like the elastic clips to secure the cover underneath the bike to prevent it from being blown off in high winds.

I've tested for water-proofness and it does indeed shed water quite well. The UV protection is what I'm most interested in, though.

We're using this cover in a bit of a non-traditional manner but its working out great for our needs.  Our bikes (not motorcycles) are stored in our greenhouse which has turned into more of a workshop/shed in the last 10 years.  We have VERY expensive road and mountain bikes and this XXXL cover works well to cover almost all of them in one shot.  Since we have some wood working tools in that space as well, it will get its fair share of action protecting the lubricated chain-rings and sensitive hydraulic brakes from getting caked on with sawdust.  Protecting our investment with such a quick, easy and inexpensive solution is a no-brainer and this product does the job quite well.

I received a discount on this item in exchange for my honest review.  I hope you find my comments helpful in your buying decision.
3836072
Its perfect. I go mountain bike trailing in all weather and it has resisted rain and hard falls. I strongly recommend it.
3790895
Nice fit, comfortable. Good investment for long bike rides.
293331
Good motorcycle cover.  Use it on an 07 GSXR 1000, fits pretty snug and quality straps to tie down the cover on your bike.  Havent used it outside yet so not sure about the water resistant feature, but it does keep the bike clean from all the dust in my garage.  And i like that the inside has an good soft cloth as so the bike won't get scratched up.
2757240
Decent. Easy to get on and stays in place. I ride to work every day.
I could see some serious riders concerned about wind and aero dynamics, but for me on my mountain bike its great.
Easy to put on, but I guess easy to steal as well.
3010426
Two trail runs in and I liked them a lot. The foot protector is noticeable but did protect. Good rock protection.
3839056
Good for mountain biking, allows forward and backward views, gives a good shooting perspective of the riders upper torso and I also like the footage of the front tire view.
3754781
Very comfortable on 85 mile ride in the mountains. Appropriate padding and gel for long haul. Not too bulky. Well ventilated.
318586
Shorts are a very good buy and are well made for the money. I have 3 pairs of them. Good for mountain biking.
1681774
Nice adjustable fit. Good looking helmet. Giro is a good brand and this helmet has served me well. I use it for mountain biking, road biking, and commuting.