"Gem" used by various manufactures for their models including, in the late 1800s, the Fitchburg Machine Works of Fitchburg, Massachusetts and more recently an English company for their round-bed lathe manufactured during the 1970s - but Seneca Falls may well have been the first, their little plain-turning Gem lathe first appearing in publicity sheets during 1889.
The lathe was intended as a simple, plain turning machine with a 3-inch centre height and a capacity between centres of 18 inches.  The 5/16"-bore headstock spindle ran in adjustable bronze bearings and carried just a 2-step,  flat pulley for inch-wide belt that could be driven by either a wall or ceiling-mounted countershaft or, at no extra cost, from the maker's unusual, and very ornamental, double-treadle foot-power stand with overhung flywheel. The treadle mechanism, which featured two independent and individually-adjustable pedals, could be operated either standing up, in which case just one pedal was used or, if more power was required, by sitting down and operating both; the mechanism was also used for some years on the company's larger lathes.
Supplied as standard with the lathe were two T rests and their bed-mount sockets, point, cup and spur centres for metal and wood turning - and a leather driving belt. Seneca Falls went on to use the "Gem" name on a range of larger machines, though they were also sometimes entered in catalogs as "Speed" models, a term usually reserved today (in the USA) for a simple headstock and hand T-rest or compound slide assembly used for polishing and very simple turning..