The Micro Traxion is a progress capturing pulley, popular for rock and crevasse rescue, rope soloing, arborists, riggers, big walls and more. It's also an expensive piece of kit, and you want to do everything you can to avoid dropping it.

Did you know the micro traxion has a hole in it that's designed for a keeper cord? Thank you, clever Petzl product designers! I’ve talked with people who have used it for years and don't know that it's there. I took a careful read through the technical documentation, and it's not mentioned in there either. (And, full disclosure, a Petzl product rep told me about it, otherwise I never would've found it myself.) Well, now you know, a secret little bonus from Petzl! =^)

You need a strong string/cord with a very small diameter to fit through the keeper cord hole. I used 1.3 mm dyneema / spectra / UHMWPE string. A mere 1.3 mm, but rated to 580 pounds, amazing! You may find something tiny (2mm?) at your climbing shop, good luck. You'll also probably need a safety pin or something similar to work it through the hole, be patient.

Now I get it, not everybody likes keeper cords. Some people find that they are fiddly, get in the way, and hang up on other gear. You'll probably feel this way until you drop a Grigri or something similar, then you'll be a convert. =^) Give it a try and see what you think, it's easy to remove if you don't like it.

(And, hopefully this is obvious, but please do not carry gear on your harness dangling only from the keeper cord. Clip it properly to a carabiner. The cord is there only if you’re a fumble fingers.)

Here’s a link where you can buy dyneema string like this. Bonus, it can also work for repairing the trigger wires of cams. (Or so says British expedition climbing expert Andy Kirkpatrick, I personally have never done this.) Share some with your friends, you’re going to buy quite a lot of it, like about 10 meters. 

An excellent carabiner to pair with your micro trax is the Petzl Sm’D. This is a modern compact D shaped carabiner, available in screw gate or double action twist gate. It has the bonus feature of a small hole drilled just below the hinge, which is designed for the other end of the keeper cord. See photos below.