Best Butyl/Butyl II rubber provides superior resistance to highly corrosive acids and is excellent for handling ketones and esters. This synthetic rubber also provides the highest permeation resistance to gases and water vapors of any protective material used to make gloves. It does not offer the physical strength of natural rubber. Butyl II provides the ultimate combination of protection and dexterity. We use only the finest quality butyl rubber in the production our Best Butyl gloves.