Description: U-type pipe can change the channel direction. The product can be connected, you can make more modeling channels. Wide Application- Suitable for hamsters, gerbils, mice and other small pets. High Quality- Eco-friendly plastic, nontoxic, odor-free, healthy and wear resistant. The pipeline has a vent, allowing them to breathe freely inside, does not affect them play playful. Specification: Material: Plastic Tunnel Inner Diameter:Approx.5cm/1.97inch Long Straight Tunnel:Approx.15cm/5.91inch Short Straight Tunnel:Approx.6.5cm/2.56inch Three Way Tunnel:Approx.9.5x8cm/3.74x3.15inch Bend Tunnel Length:Approx.10.5cm/4.13inch Package Includes: 4 piece Tunnel Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.Customer satisfaction is our primary concern. If the product is somehow cracked or broken during shipping, please feel free to contact us. We will try our best to give you a satisfactory solution.