Uxcell 160mm to 110mm ID PVC Reducer Pipe Fitting Straight Adapter Connector, White - Walmart.com
E-outstanding Quick Straight Connector 5PCS 1/4inch to 3/8inch OD Quick Straight Push Connector Water Tube Pipe Fitting Kit for RO Water Systems Purifiers Filters - Amazon.com
Coupling 2" Slip x 2" Slip for hot tub and spa plumbing
Straight Connector with 3/32" Barbs (2.25mm) ID Tubing