UMAREX PAC 400 - Super Portable Battery Operated PCP Air Compressor

The PAC 400 is Umarex’s answer to the “I want to fill my rifle anywhere but I also refuse to carry a stirrup pump like it’s 1890” problem. It’s a battery-powered, portable PCP compressor designed specifically for topping up airguns in the field rather than doing full tank fills from empty.
 
Think of it as a mobile support tool rather than a workshop replacement.
 
Key Features
18V Li-ion battery powered (Makita-compatible system)
Fully portable PCP compressor design
Up to 300 BAR maximum pressure
Fast 4 L/min (FAD) inflation rate
Oil-free and water-free operation
Adjustable auto shut-off in 1 BAR increments
Overheat protection system
Replaceable filter sponge for simple maintenance
Foster quick disconnect output
Multi-adapter compatibility (1/8", M10, M10x1)
Optional battery compatibility with multiple tool brands
 
Performance / Use Case
This is built for field topping-up, not full refills from low pressure. That distinction matters more than people like to admit.
 
With a 4 L/min flow rate, it’s significantly quicker than most portable units, meaning it can top up cylinders in a reasonable timeframe when you’re out shooting. The trade-off is that it’s not designed for deep fills from empty, and it performs best when maintaining pressure rather than rebuilding it.
 
The battery operation is the real advantage here. No mains power, no generator, no excuses. Just charge it, take it out, and use it where needed.
 
Build & Design
Despite being portable, it’s still a fairly solid unit at 6.1kg. The compact shape makes it easier to carry than stationary compressors, though it’s not something you’ll forget you’re carrying.
 
The layout is straightforward, with a clear digital interface for setting pressure and monitoring status. The automatic shut-off system reduces risk during unattended fills, while thermal protection helps prevent overheating during repeated use.
 
Noise output sits around 80 dB, which is noticeably louder than the PAC Eco, but expected for a high-output portable system.
 
Specifications
Power Supply: 18V rechargeable battery
Battery System: Makita-compatible 
Power: 180W
Rated Current: 10A
Maximum Pressure: 300 BAR
Inflation Rate: 4 L/min (FAD)
Maximum Run Time: approx. 50 minutes
Maximum Fill Volume: 1 litre per cycle
Noise Level: ~80 dB
Dimensions: 370 × 89 × 183 mm
Weight: 6.1 kg
 
The PAC 400 is not trying to replace a workshop compressor, and it’s better for it. It’s designed for shooters who need flexibility in the field and want to avoid manual pumps without committing to a full stationary setup.
 
It works best as a maintenance and top-up tool rather than a primary filling solution, but in that role it’s genuinely useful and far more convenient than traditional alternatives.

Please note that these compressors come with a Type-C Plug - you will need one of these adaptors for use in UK Type-G Sockets: Type-C/Type-E to Type-G Plug Adaptor