I have a Sealey TL81 timing light but it's a perfect fit and works well. Turns out the capacitor was actually the primary failure, but the new bulb works fine now I've replaced the capacitor too. Nice and bright. Fitting required using a soldering iron to secure it in my light, since the screen wire is combined with a spring which holds the bulb in place when twisted into position on the HV posts. I've kept the old bulb just in case, but will use the new one.