These are reclaimed bike cogs, cleaned and degreased at Steel Web Headquarters. They're all unique with individual wear patterns and aging.
Medium Cogs are 7cm to 10cm
M1 - 7.9cm diameter, 2mm thick
M2 - 7.4cm diameter, 2mm thick
M3 - 8.5cm diameter, 2mm thick
M4 - 8cm diameter, 2mm thick
M5 - 7.9cm diameter, 2mm thick