I ordered 2 of these for about $6 each.
As noted above: finish is random. I sanded the threads with emery cloth with good effect.
Neither leaked over the course of 15 dives. They get tough to actuate at depth. I didn’t use tribolube as mentioned above. Interestingly, baby shampoo (mask defog) worked pretty good as a lube, although transient.
On one light I replaced the emitter with a 16mm UV Star and it was the bomb. A lot of bang for the buck.
One wierd issue is that both lights crushed the top of 18650 cells. These were decent cells. They didn’t crush the protected cell that came with my thorfire TD26, I presume because the protection is a button on the top.
These lights are really good value for the money. If I had to leave one behind or lost it, I’d be more sad about the battery than the light, based on cost.