Victaulic Style 905 Coupling for HDPE - Rigid Plain End Pipe Joining
SharkBite 3/4 Inch x 1/2 Inch Reducing Coupling, Pack of 12, Push to Connect Brass Plumbing Fitting, PEX Pipe, Copper, CPVC, PE-RT, HDPE, U058LF - Faucet Parts And Attachments - Amazon.com
20/25/32mm HDPE PE PVC Pipe Compression Fittings 1/2" 3/4" 1" Thread Irrigation Watering System Elbow Locked Coupling - AliExpress
4 in. Corrugated to 4 in. PVC Coupler
Compression Coupling - 1-1/4" PE x 1-1/4" PVC - Geo-Hydro Supply, Ltd.
ADS 4-in x 4-in Corrugated Snap Coupler Fittings in the Corrugated Drainage Pipe Fittings department at Lowes.com