Tank Tender Tank Penetration Fittings come with 30" of tubing - for a tank whose maximum depth is 30".
For tanks between 30" and 60" deep, an Extender Tube is required.
The Extender Tube is a stiif, 30" straight tube with a brass insert fitting at one end for insertion into the distal end of the Tank Penetration Fitting. It's a simple push-on fitting.