Review on Included Bonded Thread Fitting Adapter by Philip Latham

I bought a check valve in the US and wanted to use it abroad. So I bought a 3/4 G BSP to 3/4 MNPT thread for my Rinnai water heater's shut off valve. The BDP fits my hose well. However, MNPT is not suitable for a check valve (only a few turns inside my valve and three turns outside) as shown in the picture. I wonder if it will be phased out in the future? or the adapter does not fit the check valve (Matsui)? Many Thanks?.