Ten HO scale Racor 22A Low Switchstands - priced at $3.00US per switchstand. Each kit includes eleven different targets and six styles of switch lamp and was primarily designed to model NYC/PRR/PC/CR, CP, CN, B&O/C&O, and NKP. Based on a Penn Central prototype, they were used by most railroads and are still in service today. Shims are included to allow for easy mounting on commercial HO turnouts like Atlas or Peco.
Assembly instructions are available in the Tips and How-tos section of the Shapeways 3D Printing Forum:
https://www.shapeways.com/forum/t/racor-22a-ho-low-switchstand-assembly-instructions.102702/
A magnifying headset (Optivisor) and a precision sprue cutter like the Intermountain BB-1015, Micro-Mark #82393 or UMM-USA GMT01 are required to cut the parts from the support framework.
https://umm-usa.com/onlinestore/product_info.php?cPath=21_28&products_id=3749