Concerned about our environment? We are too. Microbattery.com is the first wholesaler to actively promote Mercury Free watch batteries. In March 2008, we begin offering the two most popular watch battery sizes in the 0% Mercury, or Mercury Free design, to the wholesale trade and to consumers. If the silver oxide watch battery does not say 0% HG on the battery, then it's not mercury free. Mercury is very harmful to the environment. Watch batteries that are not properly recycled pollute the environment. Spend an extra dollar and buy a mercury free battery for your watch. Our MF watch batteries prices are acutally lower than our competitors' mercury containing watch batteries. Currently available from us in only two sizes; SR621SW (364) and SR626SW (377).