"Lightweight truck camper" is marketing language without an industry- standard definition. In practice it means somewhere between 500 lb and 1,500 lb dry, depending on the format and amenity level. Three weight classes track to three real product formats:
Truck-bed toppers: 400 to 700 lb dry. Bed-rail shells with sleeping platforms; no plumbing, no heat, no built-in interior. The lightest end of the category. Best for weekend trips and warm weather.
Pop-up truck campers: 500 to 1,500 lb dry. Lower shell with soft fabric or thin composite side panels and a roof that lifts at camp. Three-season standard insulation. Lighter than hard-sides and significantly lower-profile for driving, but soft panels lose more heat than a rigid wall and the lift mechanism is a maintenance item over the long term.
Lightweight hard-side truck campers: roughly 800 to 1,200 lb dry. Fixed walls, full insulation, integrated kitchen and bath options, always-deployed interior. The Kimbo 6 (~830 lb base dry) sits at the lower end of this class; most other hard-sides in the lightweight tier land in the 1,000–1,200 lb dry range.
Standard hard-side truck campers: 1,500 to 2,500+ lb dry. Composite-wall construction (welded frame plus laminated wall panels). More cabin volume, more amenities, more refinement, and more weight. Not lightweight. Targets full-size and HD trucks where the payload can comfortably carry it.
The lightweight question is really "which format gives me the right trade-offs at the lowest weight that does what I need?", not "what is the lightest camper, period." The answer depends on whether you need fixed walls, an always-deployed interior, four-season capability, and security when you're away from the camper. If yes to those, you're in the lightweight hard-side class; if no, the pop-up or topper class can deliver lower absolute weight at the cost of those features.
A note on naming. A lightweight slide in camper and a lightweight truck bed camper are the same product category as a lightweight truck camper, just named for the install mechanism (it slides into the bed) or the install location (the truck bed). All three terms describe the same fixed-wall hard-side, pop-up, or topper formats above. The Kimbo 6 at ~830 lb base dry is one of the lightest slide-in truck campers in the hard-side class; the same K6 is one of the lightest truck bed campers under any of the three names. Below we use "lightweight truck camper" as the canonical phrase for readability, but everything that follows applies to all three variants.