Silcock keys are for turning water spigots that have no handle.
Where did you find a heavy key acropolis5? All of the ones that i sold in the past were made out of pot metal. Here is a link,
http://www.acehardwareoutlet.com/(eigyuynnfrmrce2yjo3ymbf5)/ProductDetails.aspx?SKU=40072
Standard Disclaimer, but this should be available in the local stores also.