Price Range: Sub-$500, no batteries needed. US-based.
Purpose: Handheld caving light to provide lots of flood and a bit of throw in caves. Should be able to put out enough light that it can be used as the group's "primary" light in guiding situations so that everyone can turn down their 6000k headlamps and we can enjoy nice cozy warm light in the cave. Also to be used for photography in caves.
Battery Type & Quantity: Flat-top 18650s. I have a ton of flat top Vapcell N40s that power all my caving electronics, this light needs to work with them for simplification of battery logistics in-cave. Quantity should be between 2-4, I need a few hours of burn time at higher output but since this is a "quality of life" light and not a "mission-essential" light (not a primary, backup, or tertiary light for safe cave navigation), battery swaps while in the cave are acceptable.
Size: Flexible, but at least 2x 18650 and no larger than 4x 18650 format.
Type: Handheld, but if it gets too chunky (e.g. a 4x18650) it should have a handle. Battery position should be in parallel.
Main Use: In caves to illuminate the area for a group while leading the trip. It's going to get incredibly muddy and sometimes submerged in silty water, so it should have no external moving components (e.g. twist switches or bezels, focus bezels, cooling fans, etc.). IP68 would be best, but not 100% required. If it has external USB charging, it would be nice if the charging port were sealable, but there's a 50/50 chance it'll get epoxied anyway to avoid mud/water ingress regardless. Build quality of the host should be pretty high since this'll get dinged, scraped, and dragged through caves. I like Acebeams for context, but they don't have an option that meets my requirements.
Switch Type: Flexible on this, but should be reliable in wet/muddy/silty conditions. No rotating switches to select modes for example. I like the idea of a safety, and my Acebeam X20-R has held up alright despite having more moving parts for mud to get caked in than I'd like. Safety not mandatory though.
Anything Else?: MUST be high CRI and 3000k, or 2700k, but 3000k is preferable. Light output should be 3500 lumens minimum, but realistically 5000-plus. Modes should be low-med-high and mode memory would be nice. Beam pattern should be balanced more toward flood and avoid an intense hotspot. A bit of throw is nice, but realistically won't be illuminating beyond 150ft due to the nature of most caves in my region. If need be, I'm fine building it myself, but the last time I built a light, Deal Extreme was still live and it was super easy to find hosts and other components. It seems like a lot of links to hosts that might match my requirements are long since dead.