Rare original Thud Buster seatpost, pre-Cane Creek. Light marks from age and use, but excellent condition considering the age. I have personally not mounted/used it, nor have I tried to disassemble it to swap the elastomer, so I don't know the condition of the elastomer, but it would likely need a new one to be useable.  Excellent collector's piece for a period-correct build. 

Hardware is complete. Diameter is 27.2mm, and length is approximately 355mm (would be slightly less under sag), with the minimum insert mark being approximately 70mm from the bottom of the post. 

See pictures for details.