The Rhino bottom drains are all made from schedule 80 PVC and a tough and rugged. the little bit extra you pay for this brand is more than compensated by the good instructions, the strong rugged design and quality craftsmanship and materials.
For a PDF of the installation instructions for this bottom drain (so you can look them over before you buy) simply email Nate@practicalgardenponds.com and ask for "Rhino II Installation Instructions".