Our take
Choose the PJ770B when the battery and local/external media options answer a real portability need. Its native 720p resolution and 90 ANSI lumens define a small, controlled-light use case; confirm the battery, light engine, and ports on the particular unit.
Portable movie or photo viewing with a local source, speaker, or compact HDMI device.
It is not for bright-room projection, a large detailed home theater, native Full HD or 4K, or a buyer expecting Bluetooth to carry video or provide streaming apps.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- GPX specifies native 1280 × 720 and 90 ANSI lumens for the exact PJ770B.
- The built-in rechargeable battery and carrying handle support temporary placement.
- Two HDMI inputs, local USB/microSD playback, and Bluetooth audio provide different source paths.
What to weigh up
- The low ANSI rating limits use with large images or ambient room light.
- GPX rates the battery for up to two hours; age and actual capacity matter on a used unit.
- Bluetooth sends audio to an external speaker and is not a video-streaming connection.
The key details
| Model covered | PJ770B |
|---|---|
| Image format | 720p 1280 × 720 native |
| Rated light output | 90 ANSI lumens |
| Placement | Battery-powered; GPX rates use up to 2 hours and a 3.3–16.4 ft display distance |
Performance figures are manufacturer claims. Source checked October 9, 2026. Regional models and included accessories can differ.
What the features mean for you
What does 720p mean for a portable image?
GPX identifies the PJ770B's native image as 1280 × 720, or 720p, and specifies 90 ANSI lumens. That combination suits a modest picture in a controlled-light setting more naturally than a large image in a bright room. A video source may send a 1080p signal, but the projector's native panel remains 720p. Buyers deciding between portability and detail should keep those specifications separate: the battery removes a power-cord constraint, while the panel and brightness still set practical limits on picture size and room light. Check the intended screen, viewing distance, and seating before treating the maximum size as a target.
How does the battery change setup?
GPX describes the PJ770B as rechargeable and rates battery use for up to two hours. That can make a temporary movie or photo setup possible without a nearby outlet, but it is a model rating rather than a promise about an older battery. Runtime depends on age and use, so ask about charging behavior and test the exact unit if cordless viewing is essential. The projector also operates from its AC adapter, which remains useful for longer viewing. Its carry handle and compact body make moving the unit easier, but buyers still need a stable surface and suitable projection distance.
Are local files and Bluetooth the same as streaming?
The PJ770B includes USB and microSD playback for supported file types and has two HDMI inputs for external players. Its manual lists limits for storage size and media files, so check whether the content and drive formats you plan to use are compatible. GPX also documents a Bluetooth transmitter for sending audio to a speaker or soundbar. The transmitter does not carry video, and the model does not replace a device with installed streaming apps. For online shows or a laptop presentation, connect an appropriate external player through HDMI. Verify the remote, adapter, and storage behavior before relying on a used package.
What placement range should be measured?
GPX gives a 3.3–16.4 ft display distance and a 30–150-inch viewable-size range. That supports checking whether the projector can sit on a table or shelf at the distance the room allows, but the largest advertised diagonal is not a promise of a bright or sharp image at that size. The projector is not an ultra-short-throw design. Measure screen width and lens-to-screen distance, leave room for ventilation, and confirm focus at the chosen position. The model guide documents manual focus and angle correction; those adjustments help alignment but do not change the resolution or raise the brightness rating.
Who should compare a brighter or more detailed alternative?
The PJ770B is the portable choice here when battery operation and its built-in local player matter more than output. The AAXA P6X offers a different battery-oriented format with a documented WXGA panel and separate output modes, while a fixed model such as the LG CineBeam HU710PW has 4K UHD output and 2000 ANSI lumens but requires conventional AC-powered room installation. Those are different ownership patterns. Choose the GPX for modest temporary viewing and a self-contained source option; choose a higher-output fixed projector for a larger, more detailed image. No recommendation assumes an individual PJ770B battery still meets its original rating.
What else to compare
AAXA P6X adds a documented WXGA panel and different battery modes; LG CineBeam HU710PW is a fixed conventional-throw model with 4K UHD output and a 2000-ANSI-lumen rating, but no battery portability.
Before you buy
Can the PJ770B run without wall power?
Yes. GPX documents a rechargeable battery and rates cordless use for up to two hours; older battery condition varies.
Does its Bluetooth connection stream movies?
No. GPX describes Bluetooth as an audio transmitter for speakers; video comes from HDMI or supported local files.
Is the PJ770B native Full HD?
No. GPX specifies a native 1280 × 720 panel, so a higher-resolution input does not make it Full HD.
Where can I check the current price?
Use the Amazon link for current offers. Check the exact model, seller, product condition, delivery, and return terms. This page does not display a live price or confirm stock.
Sources & review basis
We use the following manufacturer documentation for the product features above. Our suitability notes and buying advice are editorial judgments based on those features, not measured performance results.
- GPX PJ770B product specifications and FAQ ↗ — checked October 9, 2026.
- GPX PJ770B product specifications and FAQ ↗ — checked October 9, 2026.
- GPX PJ770B model user's guide filed with the FCC ↗ — checked October 9, 2026.
The decision
The PJ770B is for portable, modest-size viewing where battery and source flexibility outweigh its 720p resolution and low brightness.
Is it the right fit?
Check the exact model and today’s offers on Amazon.