Here is a fine 138 link, #25 chain for a variety of electric scooters.
This chain is compatible with the Razor E500S, and it may also fit other brands of scooters and electric recreational vehicles.
This chain measures 1/4" in pitch (pin to pin distance), and is precut to length. It consists of 138 links (69 inner links + 69 outer links). Chain this size may also sometimes referred to as a 138 pin chain.
⚠ WARNING California Residents:
Proposition 65 Warning