Who is the Huffy Extent sized for?

Huffy lists it for riders about 5'2" to 5'10" on 26-inch wheels with a medium frame. Check the standover height before buying if you are near either end of that range.

Does it have disc brakes on both wheels?

No. The front wheel has a disc brake and the rear uses an alloy V-brake. That is enough for paths and light trails but less consistent in wet, muddy conditions than dual discs.

What kind of riding is it built for?

It handles trails, gravel roads and town riding. The 18 speeds and suspension fork help on hills and rough surfaces, but it is not a downhill or technical singletrack bike.

How do the gears work?

Shifting is through Shimano twist-grip shifters with 18 speeds. Twist shifters are simple to learn but less crisp than trigger shifters on more expensive bikes.

Can I adjust the seat height?

Yes. The padded saddle sits on a quick-release alloy clamp, so you can raise or lower it without tools.

Is it worth it over a cheaper single-speed bike?

If you ride hills or mixed terrain, the 18 speeds and suspension fork make it more versatile than a single-speed. For flat, short trips a simpler bike is easier to maintain.