Check the listing for details. 5 PACK- DEAD END PLUG Arc Tee, New Cutting Edge Tech 5/16"Maple Sap Tees US made. Condition: New. Listed at 12.99 USD. 5 PACK - Brand New - These are the Green DEAD END TEES. These are for the last tree on your line. One barb is plugged so that the tubing section that wraps around your tree is not connected to the system, it is isolated. 5-PACK. You get 5 of the fittings pictured. These new 5/16" end of line PLUG-TEES can be used with any 5/16" ID maple tubing. One Plugged Barb goes into the tubing on the end of your maple line and when you wrap the maple line around the tree and use either an End Hook or an End Ring to secure the end of the tubing to your line.. These are used at the LAST TREE on your sap line. This prevents leaks where the tubing wraps the whole way around the tree from interrupting your sap flow. This fitting essentially blacks off the sap from entering the last piece of tubing that wraps around the tree. This section is a place where sap often pools and spoils and it's one of the squirrels favorite places to chew! So blocking it off is very beneficial! Cutting Edge Technology. These tees are the result of the University of Vermont's latest studies maximizing maple sap production. PROUDLY MADE IN THE USA. Fits 5/16" ID Maple Tubing. The ARC-TeeThe ARC-Tee provides for smooth flow of sap, less turbulence, lowers the chance of blockage, and reduces pressure head loss by about 50% compared to a 90-degree tree. Pressure Head Loss in Tubing Junctions