Most trekking bars are designed to fit ATB and Hybrid shifters, brakes, and grips. Most also have a 24.5mm stem clamp size, which is again in the ATB/Hybrid area. I found them comfortable with plenty of good hand positions, they're really good for climbing. They are pretty much the most fred-nificent bars though; far too often they have a million things clamped on to them. So I recommend them to anyone looking to upgrade a hybrid or ATB without spending loads of money on new hardware.

EDIT: I forgot to add they can be bar taped - which is awesome.