This is the second iteration of this: http://www.thingiverse.com/thing:1340098 You should use this file instead of the other one.

Edit: 02/20:

• Added holes customization options, you can define their diameter and their offset for better positioning.
• Now you have different parameters for the two different tabs, so the left and right tab don't have to be the same length.

Edit: 02/14: Several things changed:

• Easier to customize / harder to generate broken files
• Changed the internal structure to minimize bridging requirements, now all your printer needs to be able to bridge is the length of one link.
• Sturdier structure, since only half of the links are now hollow.

Try to choose an odd number of links, You will get an easier to calculate total length. When using an even number of links the .scad automatically generates a cap 1/10th of the length of a regular link to keep things together. Depending on your settings, this cap can be a pain to print.

For now there are no screw holes, i will add the option soon.