Dorrance 555 aluminum hook with nitrile covers

I also use a Dorrance 555 aluminum hook with nitrile covers. It is light, and it is extremely powerful and sturdy. Compared to the Otto Bock Movohook and right after wearing a few days, I would rate it as more precise, more sturdy, lighter and more versatile.

The rubbers were a feature that some may look at as outdated - but I would not go that far. After wearing the Otto Bock Movohook 2Grip for over a year now and after working with it a lot, I have to say that it is heavy (the Dorrance 555 is light), even freshly after a service/overhaul the Otto Bock hook's tips are not precise and neither is the Otto Bock hook joint (the Dorrance hook has a ball bearing and is rather precise), the Otto Bock hook has two spring settings (but I often only use one spring tension setting and that is the strong action one; if I need two spring settings these are 'strong' and 'ridiculously strong'), the Otto Bock spring has a slightly stronger initial resistance to pull (whereas the haptics of rubber tension is - hard to describe - pleasant to my shoulder). And the Otto Bock spring accidentally falls off, as they don't seem to fix the spring too well.

First I cut myself an adapter piece (instead of buying yet another Otto Bock bolt) and placed a washer under the ball of my cable so it would fit and stay in place.

Then I increased the hook's strength by buying some castration bands [see Open Prosthetics on that issue] and now adding one. I don't have this tool they use to put on rubber bands, so I just rolled it over the claws and pulled it into position. No problem.

Very nice. I do like the vertical claw position, also I find it better for typing.

Some more about highway robbery on a great Open Prosthetics blog page: I use castration rubber bands instead of the official rubbers that sell 40 pieces for 37 US$ or so at Alternatively they sell castration bands for 17$ a pack (without shipping) at

Now, I got 100 pieces for 15 CHF - one for 15 cents (that includes shipping and handling; price without shipping is ~ 2.70 CHF). That's a fair price for standard rubber rings that I can live with.

Get your supplies at proper stores. Not at

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Dorrance 555 aluminum hook with nitrile covers; published 06/02/2010, 23:51; URL:

BibTeX: @MISC{schweitzer_wolf_1602858183, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Dorrance 555 aluminum hook with nitrile covers}}, month = {February},year = {2010}, url = {}}