Something like these are your items?
https://awcsilencers.com/shop/amphibian-ii/
https://www.smallarmsreview.com/display.article.cfm?idarticles=2119
https://awcsilencers.com/shop/amphibian-ii/
https://www.smallarmsreview.com/display.article.cfm?idarticles=2119