Unfortunately guys at the moment I don’t have the information for every engine to know its head diameter as the manufactures don’t always list this info on their websites. The easiest way to check is just to use a ruler on the head heat sink to check its size.

There are only two casing sizes which does cater for all the .21 engines on the market, the small casing is 60mm and the large is 68mm which even fits the very large Novarossi purple headed engine range. If for any reason you change engine brands lower casings can be purchased seperatly if needed.

As for temps after only 5 mins with the Sure-Start on the lower power setting (one bulb element) and an ambient temp of 68 degrees F the engine casing is on average around 120F and the heat sink around 150F. There is even heat in the chassis at this point too. Leave the Sure-Start fitted for 10 mins and 200F at the head and 150f on the casing is easy to achieve.

If you look at the testimonials on my website you can see some of the feedback I have had on how the device works and people have been extremely impressed with its performance. And despite selling around 100 units no one has ever purchased a replacement bulb due to failure.