I must the luckiest man on the planet never having screens anywhere but on the windows for 22 years. I have had wasp nests built under my stone shield. Yet, never any in my Suburban heater or water heater, or refrigerator. There were no holes in the hose carrying bumper. The bumper had metal doors hinged at the top. Something I wish my Sunseeker had. I hate dealing with those plastic caps and got some spares in case I lose one with the hose trailing behind the RV driving down the highway. I have no plans to screen anything not made that way, now or ever.