If you go mountain biking in the actual mountains, it's fairly likely that you'll encounter situations in which you have to carry your bike. And if those situations involve activities like rock-scrambling or otherwise negotiating sketchy terrain, it would really be best if both your hands were free. It was with this in mind that German cyclist Marvin Kiesel created PeakRider, a hands-free bicycle-carrying system.
PeakRider consists of two parts. There's a small pouch that gets strapped onto the bike's down tube, along with a telescoping pole that is inserted into the cyclist's hydration pack – pretty much any pack should work, as long as it has a central opening on top for loading and unloading the water reservoir.
When it's time to carry the bike, the rider just hoists it up so that the pouch gets hooked over a knob on the top of the pole, which protrudes out of the pack. The bike is then balanced across their back, with a plate on the bottom of the pole helping to spread its weight evenly across their hips.
The whole system weighs 190 grams.
If you're interested in getting a PeakRider of your own, it's currently on Kickstarter. A pledge of €55 (about US$65) will get you one, when and if they each production. The planned retail price is €79 ($93).
It's demonstrated in the video below.