How does a quill stem without a front bolt work? Looking at quill stems I noticed this rather curious one and I couldn't imagine how it secured the handlebars without an apparent bolt. Any ideas? more images !Image--prophetes.ai

How does a quill stem without a front bolt work? Looking at quill stems I noticed this rather curious one and I couldn't imagine how it secured the handlebars without an apparent bolt. Any ideas? more images !Image

At 10 o'clock there is a wedge that holds the handlebar. Taking off the plastic cap at the end of the stem reveals the bolts for tightening the stem and handlebar.