'SSL' also stands for 'Solid State Logic
', a manufacturer of high-quality automated mixing desks
for professional musicians
, top studios, and the film industry
; it is also used as a generic term for anything produced by them. Their consoles are extremely expensive and also very large, and they do not produce a budget range.
They were founded in 1969 in Oxfordshire, in England (the same year as EMS, of VCS3 fame), but they didn't find their niche until 1977, with the 'SL4000B', a console attached to a computer which could memorise fader settings. In 1991 they devised a 'motorised' console, one which could move the faders by remote-control. Needless to say, possession of an SSL desk requires the services of a full-time electronics engineer, if only to clean out the faders.
Their website does not list prices - 'if you have to ask...'