Birzman chain wear indicator

The tool gauges the chain and indicates wear by giving an elongation value of 0.25 / 0.5 / 0.7 / 0.8 / 1.0%
Using and reading the tool values:
On 1-speed chain : if value equal to or less than 1
On 5-8 speed chain: if value equal to or less than 0.8
On 9-10 speed chain: if value equal to or less than 0.7
On 11-12 speed chain if value equal to or less than 0.5