Do I need a Waterlock and a Muffler?

[AZ Parothead]

Hi All,

Installing new exhaust for our new Beta 50. Going with an in-line Vetus system but am confused over their (translated from Dutch to English) instructions. In some places it says that a water lock is optional with a waterlock muffler. In other places is says you need both.

Current thinking is to put a waterlock right after the injection and then an NLPH In life waterlock muffler but would love to only put in one if that’s an adequate installation.

Any thoughts appreciated, thanks!