This is an adjustable height 4-way toolpost for use on a Sherline Lathe. You can have up to four different toolbits mounted ready for use.
The bottom adjusting ring base raises and lowers the toolpost head with 0.025" per revolution precision.
This toolpost takes 1/8" conventional toolbits, or square gravers. Four blank HSS toolbits are included, along with a holder for grinding the tiny toolbits, and a hex wrench for the clamping screws. Tommy bar for tightening the clamp nut will be provided in a longer 3" size unless the shown 1.5" tommy bar is requested.
Here is a review by Nick Carter of Carter Tools for my Taig lathe version:

This is new manufacture... made of steel, the old fashioned way, by manual machining... made in the USA.
Please email if any additional information is needed.