4x AAA batteries to single 18650 cell

Had this flashlight laying around, that uses four AAA batteries.

While looking at random 18650 items on ebay, I seen this plastic tube that fits around the lithium cell.

As I expected, the tube is the same diameter as the battery pack.

Therefore, for less than one dollar, was able to successfully 'convert' this flashlight to one that's rechargeable. Being that 1.2v rechargeable (non lithium) batteries don't hold their charge over long periods of time, this was a worthy upgrade to me :-)

I lucked out that the tube, fits perfectly inside the flashlight.