A Threaded headset.
the fork gyro (if have) and stem and mostly important the headset
The forks go through the head tube and headset, the stem anchors the fork and then the bars attach to the stem, so the answer is the fork and stem.
It´s the Stem, it holds the bars and match with the frame with the help of a headset.
You're probably thinking of the rotor/gyro/detangler, the thingy that allows you to do a barspin w/o getting your brake wires all messed up.
Unhook brakelines pull off gyro slam a stolen headset on there then take brake trigger buy a long cabel and hook it up......ride breakless
function of headset
BMX
you spell it BMX
Bicycles don't have head gaskets, the closest thing is the headset, the bearing between the fork and the head tube of the frame. www.bicycletutor.com, www.sheldonbrown.com and www.parktool.com are good sites to read up what's wrong and what to do about it.
Sealed just means that water and muck can't get into it. Integrated means that the bearings sit pretty much directly in the frame. Regular headsets first have cups that sit in the frame, and then the bearings rests in the cup.
Integrated Headset