A heddle is aka reed

It helps you form a shed, controlling the movement of warp yarns.

There’s loads of different kinds, but they usually look like some sort of stick or string, with a loop or hole in the middle.

In rigid heddle weaving, you’ll see the reed also called a heddle. The length of your reed is determined by the size of your loom (I have a 60cm loom, so I need heddles that are 60cm wide)