This is a brand new product on the market. It is a perforated hose cap for 3/4 inch hose or PVC fittings and can be used to vent hoses to reduce freezing, or drain AC water pipes or hoses. it also reduces mold and mildew buildup and thus allergen in the hoses or pipes if not vented. It can be used to allow a gentle watering of flowers and plants like a water can but you don't have to refill the can as it attaches to the hoses. Very useful in many situations. Made of plymer and fits both male and female 3/4 inch fittings.