The Internally Threaded Thin Edge Tunnel from the Steel Roseline® has an extra thin edge and is internally threaded, the ring is screwed on to the inside thread of the tunnel and ensures a perfect hold.
All tunnels of the Steel Roseline® are sterilisable and due to their skin friendly material harmless to allergic people.
As a beginner or an experienced person in the matter of soft stretching, this tunnel is absolutely the right choice.