Lenco Turntables? any info, opinions, thoughts?

I remember them from the late '60's and early '70's. They used an idler wheel under the platter which was moved in and out to give continuously variable speed control. They were fairly well made but not very high performance. They were used a lot in schools and PA systems as they were very rugged. Pretty mediocre rumble and flutter compared to any decent belt drive table.An interesting curiosity.