Suggested upgrades;
1. Add a small lip at the bottom of the aluminum bar to support the bottom edge of the can.
2. Replace duct tape with Velcro for quick removal and replacement of the can.
3. Add a small vertical plastic tube to each side, attached permanently to the Velcro straps. The purpose is to act as guides for the spray plunger depressing mechanism.
4. Add a third slide to the device with a small hole drilled through center, through both the hoop and the base of it. The "straw" from the spray can is inserted through the hole to direct the spray. The straw can be trimmed to length and permanently affixed to the drilled slide. Experiment with a small thin piece of felt on the bottom of this slide so as to spread the McLube before it dries in the track.
Now harken can charge $150 - 200.