I thought they have thin open end and box end, but i just look on a 17mm so flank drive plus and the open end are 8.8 mm thick...my 17mm bahco 1952m are 6mm and stahlwille open box 5.5mm and hazet 18mm double box are 6mm! Box end are 2mm on bahco and stahlwille! Dont take it wrong, i like Snap...