Shoulder harness and cable protection II

Continuation from part I.

The final prosthesis now contains my latest selection of materials, mounted by my prosthetic technician. I find them widely available, affordable, comfortable, and easy to keep scent neutral.

The steel cable runs inside a metal tube. As that presses on my arm (scars there) and as my shirt catches in between, I like my steel cable well padded.

So the steel cable is surrounded by a white-transparent Tygon 3350 platin enforced biopharmaceutical grade highly biocompatible silicon tube (see next picture). For one, that material is not irritating my skin. Secondly, it has an optimal stiffness and in that, it is much better than the previously used bike tube. Thirdly, it does not smell or get smelly.

German product info (Maag Technic, Switzerland): Silikonschlauch TYGON(R) 3350 platinveredelt, unverstärkt.  Für Einsätze zum Verarbeiten hochsensibler Substanzen in der Pharmazeutik, der Biotechnik, in Labor und Analyse oder in medizinischen und pharmazeutischen Dosiergeräten. Werkstoff Silikon-Elastomer, Farbe transparent, Norm Biokompatibilität ISO 10993, Zulassungen FDA, USP Class VI, Temperatur +200°C unverstärkt, Härte 50 Shore A.

The harness is protected using a Michelin Aircomp Latex mountain bike tube. It does not at all pick up sweat scent and it is extremely comfortable to wear. The material did not seem to discolor my clothes. Also, that part can well be swapped or exchanged as these bike tubes are widely available.

For now, this setup works well. I require a very comfortable and highly functional setup for my work and living conditions.

Six months update

Precisely half a year later this component exhibited first signs of failure. We see holes in the latex tube. Still, without washing it or soaping it down it did not absorb any sweat. I can confidently report that for my choice of clothing and for my personal sweat type this product served exceptionally well.

In addition, the silicon tube showed wear and tear as well. No scent, no discoloration and no other issues arised during the first six months of testing this material.

Both defective parts were replaced with the same.

Further plans

Currently, I have no particular further plans for this. I would like Michelin to sell uncoloured (white) or skin coloured (flesh, beige, pink) tubes, but that's it.

I am now testing a new type of strap apparently made from silicon. This seems to work similarly well. I will look for wear and tear in  six months time as well.

Cite this article:
Wolf Schweitzer: Technical Below Elbow Amputee Issues - Shoulder harness and cable protection II; published 29/10/2008, 02:04; URL:

BibTeX: @MISC{schweitzer_wolf_1628190923, author = {Wolf Schweitzer}, title = {{Technical Below Elbow Amputee Issues - Shoulder harness and cable protection II}}, month = {October},year = {2008}, url = {}}

2 thoughts on “Shoulder harness and cable protection II

  1. Wolf,

    barring time zone changes, I sure would like to talk to you about interface design concepts that for now you can pass along to your prosthetist.

    Since you couldn't see Brian Monroe here in the states, I didn't get a chance to visit with you and discuss this in person.

    Drop me an email or call me (phone number in my sig on previous emails).

    The above setup looks great!

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