chin/cage safe cat donut tunnel?

recently bought one of those felt donut tunnels for my chins and my super shy one absolutely loves it! it's rare for either of them to actually use any hides. does anyone know of any that might be made of a better material for actually putting in their cage?

tempted to glue fleece over the zipper part/mouth edge but from experience doing that just makes them want to rip the fleece off cause they know something chewable is underneath....