Birdy RM21

• Serial: P8106356
• Manufacturer: Birdy
• Model: RM21
• Primary colors: Silver, gray or bare metal
• Wheel diameter: 18in
• Frame Material: Aluminum

Distinguishing features

Sachs 3x7=21-speed, rear wheel with 3-speed internal hub and 7-speed cogs. Built in the late 1990s I believe.