A no-messing Shimano Skylark copy - right down to the black plastic caps covering the main pivots.

• Derailleur brands: SunRace
• Country: Taiwan
• Date of introduction: 2001?
• Date of this example: unknown
• Model no.: M15 SB?
• Weight: 286g including hanger plate
• Maximum cog: 28 teeth
• Total capacity: 26 teeth
• Pulley centre to centre: 56mm
• Index compatibility: 5 speed?
• Chain width: 3/32”
• Logic: top normal
• B pivot: sprung
• P pivot: sprung
• Materials: steel