This spray puts a water repellent coating on to cycling shoes or trainers. Not many cycling shoes are at all weatherproof, thanks to all that mesh, so this sounds great. But in terms of waterproof jackets, 'water repellent' seems to mean 'leaks like a sieve'. Would this spray be the same?
To find out, I sprayed my right cycling shoe with two coats of this and didn't do anything to the left. In a heavy shower, water did bead and roll off the right shoe while the left immediately got soggy. Less than a minute later my right foot was equally wet. To be fair, there's a limit to what any spray, however good, can do: water can enter via the tongue and via the mesh. I wouldn't be surprised in the long term if this spray helped preserve the look of your shoes, by making it easier to wipe off wheel-spray. Just don't expect dry feet. Marginally drier, possibly; dry, no. I'd use boots like Shimano's W101 or fit overshoes, which will keep your shoes smart and provide shower protection. Dan Joyce