English to German Marketing Sports / Fitness / Recreation

Back in the day, protecting hard climbs was a difficult and audacious affair. Slings, chock stones and pitons were as good as it got. However, climbers increasingly viewed hammered pitons as unacceptable – they were scarring and disfiguring the rock and encouraging a reliance on ‘artificial’ aid. British climbers were climbing ‘pin free’ using ***threaded pebbles*** and adapted machine nuts placed in cracks. The international focus on free climbing, clean climbing and rapidly increasing standards meant that better pro was needed that could be placed easily and with just one hand. The search was on.

Es handelt sich um einen Text über die Geschichte der "Friends" genannten Kletter-Sicherungsgeräte. Hat jemand eine Ahnung, was bei diesen pin-free-Kletterern die "threaded pebbles" waren? Tausend Dank für eure Tipps bereits im Voraus!