A product of ATCO (Charles Pugh Ltd.), this was a series of open-frame powered roller mowers made between 1921 and 1933. These were the first mass-produced motor mower for the smaller garden and were available in sizes from 12 inch (the "HY" variant) to 36 inch. Sizes up to 22 inch had Villiers two-stroke engines, while larger models had JAP four-stroke engines. Very early (1921/22) "Standards" can be identified by their frames which are oval in cross-section compared with the later "H"-section frames. Early machines had the Senspray carburettor rather than the later ATCO-Villiers unit, but as the former were very often changed during the life of a mower this cannot be taken as a hard and fast dating feature. These remain a popular mower with collectors, due in part to the very large number made.