If you need to attach your camera to a slotted lug-mount or a post you will need attach strings.

The attach string are two loops tied together with a bowline knot. It's much stronger that it might appear. Check out the details of my strength test. 

They are $2 for a pair. They come in two lengths, short and long. You can also choose any color you'd like. 

For a better visual on attaching them to your strap check my instructional page.