Check the listing for details. 10 SETS - Leader 3/16" Stubby Spouts & Check Valve Connectors. Maple Taps System. Condition: New. Listed at 28.99 USD. Made in USA - Leader Brand Maple fittings. You get 10 of the stubby spouts pictured and 10 of the Check valve adapters pictured. Stubby Spout - Pictured on the left. Has a 3/16" Barbed end. Attach your 3/16" ID Maple Tubing here. The fat end of the stubby spout attaches to your Check Valve Adapter. Check Valve Adapter - Pictured on the right. The stubby spout fits into this and then it is inserted into a 5/16" tap hole. Use a 5/16" drill bit with this system. CV Adapters have a check valve inside to prevent sap back-flow. Sap going back into your tap hole contaminates it and makes it heal faster. Using these adapters keeps your tap holes open longer so you get more sap. Scientifically proven by University of Vermont. The stubby spout can be re-used many years and you don't have to cut it off of your tubing. The CV adapters are easily removable at the end of the year and can be cleaned & re-used, or replaced annually in order to maximize yield.