Plastic Trends offers injection-molded large diameter DWV Test Tees in 10" and 12" in diameter. Perfect Fit™ DWV Test Tees feature the most compact branch in the industry. Test Tees are commonly used in DWV systems around columns or in raceways. It is in these areas that space is often a critical factor. Because of that, Plastic Trends designed a product that makes installation and testing of the system quicker, easier and less costly. Perfect Fit DWV Test Tees stand up to heavy-duty applications and are not as bulky and awkward as fabricated fittings. Test Tees are offered with both raised and countersunk plugs. Plastic Trends.