This model is another from my Greek and math letters collection. This one is a sigma, which is used a lot in math. This letter is used in math to represent a sum for certain terms. I made this model in Blender 3D, and checked it with NetFabb. This model has two holes which can be used to tie a string or a band, so you can wear it on your neck.
I really hope that you like this model, and if you have any questions be sure to comment on my models or contact me.