Description Gravity Model 75 nipple is specifically for gravity flow watering systems. Features an open, stainless-steel orifice for increased water flow at lower water pressures associated with gravity flow applications. Promotes anatomically natural drinking; ideal for animals 50 lbs or larger. 3/4" bite size and 1/2" threads. Gravity Flow Nipple Connector and locknut fits into a 7/8" hole in the side of a plastic or metal barrel, or even PVC pipe. Any of the Trojan Watering nipples can then be easily installed using pipe thread tape or pipe dope. Sealing ring is designed to provide a complete 360Â seal; also resists buckling or slipping during installation. Locknut enables easy application of torque with wrench. Sharper and deeper teeth improve bonding. Precision machined tapered threads designed to create watertight union. Screen filter keeps foreign matter out of valve. Adjusts to three flow rates. Easy to install! Simply drill a 7/8" hole in your barrel, bucket, pipe or stock tank. Install connector and locknut, then screw in nipple using pipe thread tape or pipe dope (not included). Part #13235A.