Our 2 gerbils love these tubes after initial skepticism. You can easily overcome in a longer 45 ° pitch, sometimes even vertical sections (manhole). We have a 1,20m height realized as zig-zag spiral staircase, needed for 90 ° angle and 7x 7x straight ahead (21cm) -Strecken. Both mice can easily turn even or "cross" in the two-way traffic in the pipe; to our positive surprise the pipes are also (almost did) not nibbled (so far only once to get to know). A previously tested tube of another manufacturer was gnawed fiercely, they had over the Ferplast solution but also because of their bulging curves significantly "more exposed" attack edges. Only reinpieseln do it now and then ...: - / I think it would now cruelty to animals, you take away the tube again! Absolute recommendation ...