This is a nameless and very rusty, example of a Brazilian derailleur design that also exists branded as Centauros and Cristim.

Mechanically it is partly Shimano (see the cable clamp and adjustment screw placing) and partly not - it has only one sprung pivot.

I think that this is an early example of the genre. It has a rather splendid conical headed b-pivot bolt, and a slotted p-pivot bolt. The adjustment screws and the original pulley bolt have what used to be called cheese heads (a note for younger American readers - cheese used to come in large flatish cylinders, not in pre-cut square slices or in an aerosol can).

• Derailleur brands: Centauros
• Country: Brazil
• Date of introduction: 1982?
• Date of this example: unknown
• Model no.: unknown
• Weight: 221g excluding dropout bolt and cage rotation stop
• Maximum cog: 28 teeth?
• Total capacity: 28 teeth?
• Pulley centre to centre: 51mm
• Index compatibility: friction
• Chain width: 3/32”
• Logic: top normal
• B pivot: unsprung
• P pivot: sprung
• Materials: steel