EcoFlow displayed both new stations at Hall 2.2, Booth 166, alongside its OCEAN 2 home-storage system and STREAM battery range, running from September 4 through September 8, according to WebDisclosure. The company framed the pairing under the banner "Breaking Boundaries. The Future of Smart Energy Starts Now," describing its lineup as spanning "a power station that fits in a backpack to grid-level power on a building site," per WebDisclosure.

For the PowerRock 4000 specifically, EcoFlow's materials describe the unit as flipping the usual job-site logistics: instead of routing work back toward mains power or a generator, the battery travels to wherever the work is happening, according to PR Newswire.

Wattage is the number that sells the device, but the figures on the RIVER Gen4 and PowerRock spec sheets describe two different properties, and mixing them up is the easiest way to buy the wrong machine.

Capacity, measured in watt-hours, is how much energy a battery holds. Output, measured in watts, is how fast it can deliver that energy at any given moment. The RIVER 260 Gen4's 256 Wh capacity is the fuel tank; its 300 W continuous AC output is the fastest rate it can pour that fuel out, according to Trusted Reviews.

Surge output is a third figure entirely. It's the brief spike a device can absorb for something like a compressor kicking on, not the load it can sustain for hours. That's the gap between the PowerRock's 4 kW continuous rating and its 7.2 kW surge rating, good for up to 100 seconds, according to PR Newswire. A power tool with a demanding startup draw might need that headroom for a couple of seconds. Running it all day is a different question, and the continuous rating is the one that answers it.

EcoFlow's X-Boost mode works on the output side too, letting the RIVER 260 Gen4 push to 600 W and the RIVER 520 Gen4 to 1,000 W for compatible devices, according to Trusted Reviews. It raises the ceiling on what the battery can push out in a moment; it doesn't change how much energy the battery holds.

UPS switching answers a different question again, not how much power but how fast the handoff happens when mains power drops. Both RIVER Gen4 models switch to battery backup in under 10 milliseconds, a gap EcoFlow says is fast enough that sensitive electronics, a router or a medical device, keep running through a cut without an interruption, per Trusted Reviews.

EcoFlow says the 260 Gen4 is about 29.7% smaller and 16.9% lighter than its RIVER 3 predecessor, while the 520 Gen4 is roughly 59.1% smaller and 23.5% lighter than the RIVER 2 Max, according to Trusted Reviews.

Charging is quick on both models. The 260 Gen4 reaches 80% in 42 minutes and full in 57 minutes; the 520 Gen4 hits 80% in 50 minutes and full in 66 minutes. Both support 140 W bidirectional USB-C charging for solar and car setups, per Trusted Reviews.

EcoFlow also lists an Emergency Power Reserve mode that extends usable power once the display reads 0%, plus a Refrigerator Runtime Mode aimed at keeping cooling running longer during outages. Operating noise stays below 30 dB under a 200 W load, according to Trusted Reviews.

The company says active idle power draw runs about 30% below the industry average, though EcoFlow ties that figure specifically to devices drawing under 100 W rather than to every operating condition. A fully charged unit is said to retain roughly 99% of its charge after a year in storage, per Trusted Reviews.

Paired with EcoFlow's 60 W lightweight solar panel, the company describes the RIVER Gen4 setup as one of the smallest and lightest solar generator combinations on the market, according to WebDisclosure. Both RIVER Gen4 models use LFP cells, though EcoFlow's own press materials disagree on how many battery-management protections they carry: one release cites "more than 20," another cites "40+," a discrepancy worth flagging before either number gets treated as settled fact (Trusted Reviews; WebDisclosure).

The numbers side by side make the contrast easier to read:

All figures above come from EcoFlow's own announcements, per Trusted Reviews and PR Newswire.

EcoFlow positions the PowerRock 4000 for professional applications including construction, events, film production and emergency response, according to PR Newswire.

One notable feature is a built-in residual current device that EcoFlow says detects 30 mA of electrical leakage and cuts power in under 300 milliseconds. EcoFlow says the built-in RCD removes the need for separate inline modules on European job sites, and the company's release labels the feature an "industry-first," marking the term with an asterisk but not further explaining it in the materials reviewed for this article, per PR Newswire.

The housing is all-metal and IP65-rated, wrapped in a reinforced roll cage, and EcoFlow says it survives a one-meter drop despite the unit's 38 kg weight, according to PR Newswire. On charging, EcoFlow claims AC charging reaches 80% in 48 minutes and full in 60 minutes, and that alternator charging turns the drive between job sites into charging time, per PR Newswire.

The PowerRock 4000 carries a three-year warranty and officially launches across Europe today. EcoFlow says wider distribution will follow through professional electrical, hardware, building materials and tool suppliers starting in November 2026, according to PR Newswire.

EcoFlow's announcements reviewed for this article list no European pricing for either product, and no release date for RIVER Gen4. That leaves an open question about how either device will be priced against rival portable and industrial power stations once it reaches shelves.

Most of the performance figures cited above, including the idle-power savings, the year-long charge retention rate, the noise level and the RCD's "industry-first" status, come directly from EcoFlow. No independent runtime, safety or durability results were included in the sources reviewed for this report.

The PowerRock 4000 has the clearer near-term path to market: it launches across Europe today, September 4, and reaches professional distributors more broadly starting in November. RIVER Gen4's pricing and release timing remain undisclosed in the materials available so far.