stock–in–trade 
/ˌstɑ:kənˈtreɪd/ noun
/ˌstɑ:kənˈtreɪd/ noun [noncount] : something that someone or something does or makes very well and often
▪ Ballads were her stock-in-trade. ▪ Sitcoms are the stock-in-trade of the major networks.
▪ Ballads were her stock-in-trade. ▪ Sitcoms are the stock-in-trade of the major networks.
