products I own, 3.7V Li-ion-related

flashlights

Convoy M21H — 21700

[UI manual]

• purchased options — LED type = XHP70.3 HI R70;   Color temp = 5000K;   Battery = Vapcell F63 6250mAh

Convoy M21C SST40 — 21700

[UI manual]

specs:

• brightness — 780 lumens normally, with a turbo up to 2000 lumens (but the battery + heat dissipation only allows it to run for 9 minutes)
• beam angle — 9°
• beam pattern — There's a central small and bright region, and then a much larger and somewhat dimmer outer region. I love this as a general-purpose flashlight, because with a twitch of the wrist, I can decide to paint something with either the brighter or the dimmer region.

Convoy S6 — 18650

[UI manual]

• purchased options — LED type = SFT40;   Color temperature = 5000K;   Driver = 5amps 12groups linear;   Battery = Vapcell F38 3800mAh

Convoy S8 SST40 — 18650

specs:

• brightness — 600 lumens
• beam angle — 20°

UltraFire WF-501B — 18650

specs:

• ...

GearLight S1050 — 18650

specs:

• batteries compatible with — either an 18650 inside a plastic sleeve, or three AAA batteries
• beam pattern — a really lovely even spread
• beam angle — unknown, but has a zoom with a great range of angles (This and the above feature make it great for mini-scale photography on the go.)

SKILHUNT H200 mini headlamp — 18350

[UI manual]

specs:

• [amazon]
• purchase options — the mini variant, and the emitter is Nichia High CRI 4500K
• high CRI
• brightness — 580 lumens, with a turbo of 1100 lumens that lasts 60 seconds
• batteries compatible with — 18350

Convoy S2+ ultraviolet 365nm — 18650

• ...

Nitecore UMS4 — battery charger

[manual]

Batteries compatible with:

• IMR (lithium ion manganese), Li-ion, and LiFePO4 — 10440, 14500, 14650, 16500, 16340(RCR123), 16650, 17350, 17500, 17650, 17670, 17700, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22500, 22650, 25500, 26500, 26650, 26700
• Ni-MH and Ni-Cd — AA, AAA, AAAA, C, D

XTAR PB2S — USB C power bank

[manual] (backup)

specs:

• does fast charging compatible with QC3.0 and PD3.0
• batteries compatible with — 18650, 18700, 20700, 21700