You just got suited up for a night dive in St Somewhere you check you're UK DiveLight and you discover the bulb is burned out! Pre-dive equipment preparations are serious business. Missing or broken equipment can ruin an otherwise perfectly planned dive. Just keep a spare bulb in your dive bag. This is definitely one of those items that you want to never need, but want to have on hand in case you do.
Please Note: This will not fit old (purchased prior to 2008) SL6 Lights