Printed with ABS, this connects a flexible 5/16" PVC tube, to a rigid 1/2" Schedule 40 PVC pipe.
Conventional PVC/ABS cement will make the connection permanent, and water-tight.
Flexible clear vinyl tubing: 5/16” ID, 7/16” OD, http://a.co/6vksBtx
PVC Pipe Schedule 40 ½ inch: 21.5mm OD, 16mm ID.
I used this connector for my Solar Powered Submersed Sump Pump - https://www.thingiverse.com/thing:3121422