Review on Reliable A4C Submersible Splice Installation: A Must-Have for Effective Results by Joseph Morris

Works great. I have used them many times. First you need to connect the conductors. I recommend crimping and soldering metal connections. You will need to install the heat shrink tubing before connecting the wires and move the heat shrink tubing away from the heater to make the connection. After the connection, put the heat shrink tube on the connection and then shrink it. I just used a heat gun for heating. As the insulator shrinks, you'll see it, so you can move the heat gun around to get even shrinkage. For best results, you must heat all the way around the joint. Towards the end of the shrinking process, material comes out from under the shrink sleeve. This is normal and indicates the presence of a seal. A complete seal shows no air bubbles in the joint area.