Been using CarPro Reload for a few years now after a recommendation from a professional detailer. It's water-soluble (if that's the right word?) so you can let it down to go further. You can apply when the car is dry or, much easier, in the final stages of drying it. Very easy to apply and never leaves any reidue. Provides a good seal, and a lovely shine that sees rain beading on the bodywork and running off. Used other seals, waxes, show glazes, this is as good as any and easier to apply than most.
Doesn't last the "up to 6 months" but it's so easy to put on, I do it every 3 or 4 washes.