Any 9-speed-specific chain can be used with the Tiagra kit. It's okay to use others, but the Shimano chains are as good as any in terms of longevity and performance, as long as they are regularly cleaned and re-lubed.
The chain is supplied with a joining pin partly fitted and there's a spare pin too. While it was previously possible to rejoin the chain without one, we recommend using a new pin every time.
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