A robot whose weight is between 800.1 kg and 1200 kg. Beyond that a bot is in Ultraheavyweight territory. A custom component called an anti-ballast, which has negative weight, is used to create the robots then removed when finished building. Nowadays, however, SHW bots are created by using Serge's mass limit removing tool in Sergepatcher/RA2CF.
Originally SHW was used to name all bots above 800 kg with no upper limit in weight (it is occasionally used as such by the oldest members), but then it changed from 800 to 1200 kg with the introduction of Ultraheavyweight