First off there will be 10 posts so please hold off on a response till it's done if you can. These are too large for N or Z, the smaller ones are O.K. for HO and the medium and large are excellent for S, O and G. These are not cheap ( by my standards ), I can here Pete or Mike or Vic saying that guy ain't never had no standards! . The cost is about $3 each when you get used to making em'.The main parts are "Forest in a Flash" and caulking (any kind that's not 100% silicone).