Got a 25.8mm micro-adjust two-bolt seatpost right here on my desk. The lone decal reads "Instaloc", no other makers marks other than "25.8". The fancy clamp design inn black ano suggests high-end American-made after-market seatpost.

'Fraid I'm not willing to part with it.

As I recall it came off a Mongoose All Terrain Pro of 1980s vintage. Don't know if it was stock.