This is a simple Coral Reef Frag Plug for your salt water aquarium. It fits perfectly in an egg crate slot. It has a small hole in the top for holding glue. It weighs about 1/8 of an once using PLA at 100% fill. It sinks!We discovered there are 2 sizes of egg crate. Ones with 14mm wide and 13mm wide holes. So, be sure to download the right file for your egg crate. You can also scale it of course but the 13mm and 14mm versions have the same head size. Print it out, cut off a piece of your coral, glue it to the plug and insert it into an empty slot in your egg crate. Super easy, super cheap!You can now also download it in a 12 pack!Also, be sure to check out Shane's frag plug http://www.thingiverse.com/thing:16982