If you don't want to use soft tubes or petg tubes, bitspower's crystal link tubes are an excellent alternative. The rigid acrylic tubes can be cut to the required length and bent into the desired shape using a heat source such as a hot air gun. The crystal link tube has a length of 100cm, an outer diameter of 12mm and an inner diameter of 10mm. Bitspower's compatible fittings are the c47, c48 a...