BOLL guarantees the highest product quality through this Quality Management Program. Quality Assurance BOLL filters are the result of decades of Research & Development aimed at improving filtration technology. BOLL designs are highly developed and constantly improved upon, using the most modern manufacturing methods. BOLL filters are produced according to the highest international standards of quality and reliability. BOLL applies the most stringent quality controls throughout the whole manufacturing process, from the receiving of raw materials to the dispatch of the finished product.