One year ago I taped a normal business card holder in my office door glass and put my business card inside. My neighbor is a fitness centre, a lot of customers pass by my office, so I distributed lots of business cards and get some business. Because the card holder is no-weatherproof, my business cards always wet or fly away after rain or heavy wind.
Two weeks ago I sticked outdoor weatherproof business card holder in my office door glass, and put lots of cards inside, I never worry heavy rain or wind anymore. I promote my business anytime and no cost.