We are a professional manufacturer of electronic densimeter, we have worked in this area for about 20 years. We have jewelry densimeters/gold tester and industry densimeters. 
The jewelry densimeters can test the karat and density of gold, purity and density of platinum and so on. 
And our industry products can test the density of permeable and impermeable products, and they are moderate in price and superior in quality, and appreciated in many foreign companies.