Levelz ダブルエルゴシリコンコックリング ブラック

Wasn't sure about the dual shaft-and-ball design at first, but it actually stays put through the whole session instead of sliding around. The stretch is firm without pinching, and cleanup takes about ten seconds under warm water.

The silicone has just enough give that the ball ring doesn't pinch, and the stretch is noticeable without feeling tight. Wore it for a couple hours with no irritation at all.

Wasn't sure about the double ring setup at first, but the silicone has just enough stretch to fit comfortably around both without pinching. It really does add firmness and the stretch on the balls is a nice bonus.