http://www.dhv.de/web/en/newsdetails/article/sollbruchstellen-fuer-uls/

The DHV-Technology Department has tested following predetermined
breaking point at the 11.03.2013 and recognized for the UL-tow with hang
gliders:

Breaking point in stainless steel with the breaking load values of 90, 100, 120
kg

Manufacturer: Georg Schumacher, hedges mill 2, 69483 Wald-Michelbach, Tel.
0177-5969361, E-Mail: <gs>

The breaking point optionally offered with a target breaking point protection,
which allows a simple, tool-free replacement of the breaking point.

Mark Dowsett <<mark>>
writes:

We tried these ourselves last year for our winch towing but they
failed miserably. I can see them working for aero-towing as stated where the
load is rather constant but when we transition during our two-stage towing (one
line over, one line under), it shock loads the tow line and will break these
calibrated metal weaklinks in a heartbeat.