This spice shaker has a single hole on top. The hole is a bit larger, perhaps by 80 to 100%, than what you might find in most commercially available ceramic shakers due to the design guidelines for the Shapeways ceramic process.
The bottom of the shaker has a one inch diameter hole designed to accept a rubber bung or cork. The #6 red rubber bungs available from this source work very well:http://ceramicsandbeyond.com/estore/index.php?main_page=product_info&cPath=5_65&products_id=286
You can find this type of rubber bung from several online vendors. Other bungs may end up being tighter or looser than this red design. If you happen to have a bung that is too loose you may be able to create a more secure fit using a donut shaped cardboard insert to eliminate any gap between the bung and the bottom of the shaker.
You can purchase this shaker in different individual colors to contain the various spices you like to use.