IceToolz chain checker (62C4) Go/No-Go is a stainless steel device for measuring bicycle chain wear. Simply hook the tool between a pair of links and lower the opposite end down.
If the tool sits between links then it is an indication that the chain has stretched and may require replacement.
Instructions are also printed on the tool itself. Gives 0.5% and 1% indications for wear.
Dimensions: 125 x 40mm