My intake is the only one that I know of that you can change from the stock air box to one that sucks air from the fender well..
You can have the open air intake on your PT .. when it starts raining then take the 2nd pipe off.. connect the first pipe to the stock air box and you are done..
If you already have another open air filter intake on your PT the only thing I can tell you is when you go through a big puddle let off the gas.. then you are not sucking in air and will reduce your risk of sucking in water.. I wouldnt be worried about sucking in sand... any good filter will prevent that from happening..
Adam
www.prototypepower.com