(Note: I know the Sofirn SC31 Pro was first reviewed in 2020, so I apologize for being years behind)
In 2018, I got a good deal on eBay for a Surefire E1B-MV E1B Backup (MaxVision) Flashlight. My plan was to use the body with a Malkoff Devices MDC Li-ion LMH V2 Cool Head. I carried this for years, until, on a trip to New York last December, I forgot it in a friend’s apartment. Fortunately, he FedExed it back to me the next day, but it got me thinking about the replacement cost if I had lost it.
I looked on eBay for recently sold Surefire E1B-MV E1B flashlights. One sold in January 2026 for $150. Currently, the Malkoff MDC LMH Head is $103+shipping. That made me start thinking about an “I won’t cry if I lose it” (that’s what ChatGPT called it) replacement.
I used ChatGPT and Gemini to start searching for a cheaper replacement. I started out comparing 14500 flashlights, even though I ended up getting the Sofirn. Using AI saves a lot of time finding and comparing things.
On eBay, I found a great deal: $23 (USD) for a Sofirn SC31 that had a short tube, magnetic tail cap and 18350 battery. I found a Reddit discussion on how General_Specialist had modified an SC31 with a Convoy short tube. The more I looked at his photos with the Convoy short tube, the worse the Sofirn short tube looked to me. I bought the Convoy 18350 battery tube and pocket clip (black metal clip for S2 / S2+ / M1 / C8) from gadgetconnections.com. They got them to me in a few days.
When I got the Convoy short tube, the flashlight wouldn’t turn on when the end where the pocket clip attached was closest to the tail cap. I assumed it was the anodizing, so I removed some of it from the threads, but it still didn’t work. A little more research revealed that the end of the Convoy tube wasn’t making contact with the circuit board in the head.
I thought a copper washer would be ideal. The closest thing I could find (with the amount of effort I wanted to put into looking for it) was a copper gasket (washer) that’s used with an oil drain plug on a car. I found some close to the diameter of the head and figured I could Dremel it down to fit. I ended up getting an O’Reilly Dorman AutoGrade Oil Drain Plug Gasket – 097-827CD.
Using a Dremel 407 Sanding Band (affiliate link) and holding the washer with a small vise grip (affiliate link), I tried to reduce the diameter of the washer while creating a somewhat round shape that would fit inside the SC31 Pro head. I also removed some of the material from the inside of the washer, so it wasn’t so close to the positive (spring) contact in the head.
The final mod I’ll do is to replace the LED, because of the slight green tint.