Standard 4mm (inside diameter) universal air line tubing. It is ideal for use with airstones, air-operated ornaments and air-driven filters. Length: from 1 meter up to 100 meters. Select the number of meters that you need - you will get it in one piece. You choose what discount do you want. 2 meters - 2% OFF, 3 meters - 3% OFF etc. Up to 20% OFF! Enjoy!