1/2" Inch NPT to M20 Thread Adapters ($8.14 Each - Sold in 10 Pack) 1/2" Inch NPT threads on external side. M20X1.5 threads on internal side. Nickel plated brass adapter with o-ring gasket.
SAR 425
M20 to 1/2" NPT Thread Adapter (10-Pack) - M20x1.5 to 1/2" NPT Nickel Plated Brass Adapter with O-Ring Gasket
SAR 441