Amazon.com: MECCANIXITY PVC Rigid Round Pipe 12mm ID 16mm OD 200mm Clear High Transparency for Water Pipe, Aquarium, Fish Tank : Industrial & Scientific
Polycarbonate Tubing, 1 7/8" ID x 2" OD x 1/16" Wall, Clear Color 36" L: Industrial Plastic Tubing: Amazon.com: Industrial & Scientific
Amazon.com: uxcell PVC Clear Vinyl Tubing, Plastic Flexible Water Pipe 25mm ID x 28mm OD, 1m : Everything Else