The ornamental design for a roller for mirror-finishing, as shown and described.
1. Roller for mirror-finishing
1.1 : Perspective
1.2 : Front
1.3 : Top
1.4 : Left
1.5 : Front view in use
1.6 : Back view in use
1.7 : Top view in use
1.8 : Bottom view in use
1.9 : Left view in use
1.10 : Right view in use
1.11 : Perspective view in use
The broken line showing of a roller for mirrorfinishing is for the purpose of illustrating environmental structure and forms no part of the claimed design.