Jerry Peck
More important than where the parts or fixtures are made or where you buy them is the market the parts or fixtures are made for.
Parts or fixtures made for the US market will be sized for, and have fittings to match, those used in the US market.
Parts or fixtures made for the Japan market will be sized for and fit those used in Japan.
Very few items have one global standard size. If you want to use a Japan standard part or fitting in the US, the part or fitting will likely NOT fit the connecting parts or fittings used in the US.
Think of buying a Jaguar automobile. You can buy one in England with right hand drive for the British market or one with left hand drive for the US market. They will both fit the roads, and you will fit in either, however, you will find problems trying to drive a left hand drive US market car in right hand drive England, and vice versa. (Good thing they are not designed by Microsoft and Apple, they would only work on specially striped roads and would not be interchangeable.)
