The cap nut for the Magura HS 33 brake hoses.
Magura spare part
The cap screw is used to secure the brake line of the HS 33 brakes to the brake body. The clamping rings and crimp sleeves are also required for this.
Herstellerinformation: Magura, Stuttgarter Straße 48, 72574 Bad Urach, Germany, http://www.magura.com