Replacement tubing for the Filstar Filters consists of two, 6.5 foot lengths. This is the orginal tubing that come with the Filstar XL. It fits all Filstar Filters including S, M, L, XL and the original Rena XP1, XP2, XP3 and XP4. Also fits the API/Rena Nexx Filters.
The inner diameter is 21mm and the outer diameter is 26mm. This is approximately 5/8" id by 3/4" od. This tubing is specially formulated for use with the Filstar filter system. It does not contain any chemicals that can leech into the tank and cause pollution. The tubing is also formulated with a high silicone content to remain soft and pliable for a longer period of time while not kinking.