Originally Posted by bassboy

There's a few options mate...

Gtechniq G1 or G4 I think it is. Lasts the longest. Great protection. Some people have difficulty in applying and removing. Screen needs to be 101% clean - no other polishes or products can be on the screen. Product needs to bond directly onto the screen surface otherwise the results won't last long.

Any normal car wax - works great. Easy solution. Any of the proper car waxes work fine on glass - AG HD wax, dodo juice etc. repels water well. Lasts a fair while but that's dependant on what wax you use.

Rain x - my personal favourite. Easy to apply, easy to wipe off. Lasts around 1-2 months if not a tad longer. People don't really rate it highly and suggests is comes off with frequent wiper use. The more you use it the better the results. Water runs off my screen at 25mph and don't need to use wipers above that speed. I found the trick to using it is put the product on all windows, let it dry for about 10-15mins, put another layer on top of the initial layer. Leave for 5mins. Wipe off. One bottle will last you ages. I can probably do 2 cars coated around 30 times each with the above method