Black Acrylic Tunnel.
 
The Tunnels from the Acrylic Line are made of extremely lightweight acrylic which is not sterilisable in an autoclave.
It is externally threaded, the ring is screwed on to the outside thread of the tunnel and ensures a perfect hold. Due to their skin-friendly material, the tunnels are also suitable for allergic persons. As a beginner or an experienced person in soft stretching, this tunnel is absolutely the right choice for you.
 
The price is per unit. Add 2 if you want a pair.