A tutorial with no voice-over, just BGM and a few captions. Three Beiliang 18650s (shopping screenshot ¥9.50 each, 5550mWh flat-top) are placed side by side and spot-welded into a pack with nickel strip on an AWithZ handheld welder (0–30s), wrapped in blue heat-shrink and shrunk with a heat gun (34–49s), with red and black leads brought out at both ends. The body is grey PVC water pipe (shopping screenshot ¥2.77), marked with a whiteboard marker and cut open with a utility knife (63–98s); a 16mm 12–24V metal latching push-button switch (90s shopping screenshot) and a DC jack (148s screenshot) are fitted; the head is an LED e-bike headlight (square, multi-LED), lit up at 111s. A 50mm-ID grey PVC pipe cap serves as the tail cap (155s), the pack is pushed into the pipe and wired (171–185s), and a hot-glue gun fixes the head and the connectors (187–194s). Night test: a casual try outside the front door with the spot head while it is not fully dark yet; in full darkness outdoors 150 m should be no problem; a flood-beam version is shown for comparison (207–223s); the ending shows several finished units. Of 1013 comments only 11 were captured: the top one is ‘your 10 flashlights aren’t as bright as my one’ (the creator replied); someone warns that with no charge/discharge protection it will over-discharge and an external charge protection is needed, and asks how to charge it; the creator’s pinned comment adds ‘Demacia G40 gear 2’ as a brightness reference.