This kit includes four smaller end fittings that attach the lines to the struts and valve blocks, two larger fittings used on the later all plastic valve blocks between the block and the compressor, 1 meter of 4mm high-pressure line, two splice connectors (if you have to replace a broken or cracked plastic high-pressure line), and one gapping tool to modify the locking ring if the nylone line can not be pushed in. Be sure to watch the on-demand video so you fully understand the modification process. These are "push-on to lock" in place. The fittings can replace ones that have been broken or are leaking air. You can use the line to splice in a damaged or leaking pressure line.

Product Details
Here, Kent is using the included gapping tool to spread out the locking ring just a "wee bit". This will make for a much easier installation of the air line. WARNING: DO NOT spread out the locking ring past what Kent recommends in the video instructions, or you will end up breaking it in half.
If you own a W220 or a W221, you will want to get Kent's special wrench to remove and install the air line fittings under the rear shelf above and behind the back seat. See the related products below: