These Perma-Loc Tape x Barb Tubing Takeoff Adapters are designed to connect 5/8 drip tape to poly tubing using a barbed takeoff. Use the 3.6mm barb to connect 5/8" drip tape to any 1/2", 3/4 , 1 , or larger mainline poly tubing and the 7.0mm barb to connect 5/8" drip tape to any 3/4 , 1 , or larger mainline poly tubing. (Due to restrictions caused in the line, the 7.0mm barb is not recommended for use with Poly Tubing.) The barbed takeoff adapter, allows the user to run a line of drip tape from the poly tube mainline down the row. The small 3.6mm barb fittings are not compatible with 1/4" (.170" ID x .250" OD) micro-tubing.After laying out your mainline tubing at the head of the area you want to water, use the appropriate punch tool to make a hole in the mainline where you want each line of drip tape located. Insert the barbed end of the takeoff adapter into the poly tubing and attach the tape to the perma-loc end of the Takeoff Adapter per the instructions below.