I want to tweak the fit of my '83 Trek 730 slightly by replacing the original stem with one that's shorter in the horizontal dimension, to bring the bars a little closer to the seat. I want a stem that looks similar to what I have now, just for aesthetics. I'm pretty sure it's a 1" quill. I measured the thickness of the bars at the center at 25.4mm. The horizontal length of my existing stem seems to be about 110mm (center to center). On eBay I see some Origin 8 stems that seem right, but there's one dimension I don't understand. Can someone tell me what part of the stem has a dimension of 22.2mm?

Copied from eBay description:
# FORGED ALLOY POLISHED
# 60MM CENTER TO CENTER
# -17 DEGREE ANGLE
# 22.2 x 180MM LENGTH QUILL
# 25.4MM CLAMP
# 1" QUILL

Thanks,
Dan