Sparrows Tension Wheel - Circular Tension Tool

Ok, so I understand the concept but i dont seem to be able fit the two prongs into the keyway, as they are too far apart... I may be missing a trick. Can't find an instructional demonstration on mytube 🫤

Sparrows tension ring

Good item a great addition to an epg

Works really well, excellent build quality and crucial for anybody having difficulty finding correct tensioning pressure to use. Excellent feedback even though the wheel is thick and study you can still feel the pins