SEI MIO - オープンインビテーション - 頑丈なOリングガグ

The O-ring is genuinely sturdy and doesn't give at all once it's on, which is exactly what I wanted. I was worried the straps might dig in, but they didn't leave any marks even after a longer session.

The O-ring is rock solid and holds its position without shifting, which made the whole session feel secure. Soft enough around the edges that I didn't get sore even after a while. Exactly what I needed.

Finally got around to testing this out and the O-ring holds the mouth open exactly as described while the soft straps sit comfortably against the skin for a full session. The sturdy build gives me total confidence to hand over control, and it’s actually become our go-to for quiet moments.