Thank you - I had a vague memory of a light like that, and the S15 is the one I was thinking of. If memory serves, when Selfbuilt reviewed it, he found that it was OK with 1×AA and good with 2×AA, but strangely inefficient with 3×AA.

I didn’t see the point of that, so I never bought one. If I’d been thinking, I’d’ve bought one and used it with all the extensions, but only 2×AA and an AA short-circuit spacer. I like long lights, I always feel like I’m going to fumble anything less than about 125mm.