Hi, I recently purchased a Giant Bowery frameset off of ebay and built it up. The Bowery has an integrated headset and I'm not really familiar with these. Attached is a picture off all the parts I received for the headset. I've highlighted a part I'm not sure what it is and where it goes. Right now I have it placed on the the fork towards the bottom with the bottom of the head tube. Now there's a gap and it looks to me like something is supposed to go there but I'm not really sure. Your help would be greatly appreciated. Also attached are the pictures of the headtube and fork.