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VIAIR 400P-AUTO Automatic Portable Compressor (part 40045)
Model: 400P-AUTO / 40045 (page alias: 400P-A) · US configuration
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Part 40045 combines a 12V clamp connection, long hose and trigger gun. “Automatic” refers to the manufacturer’s kit/pump language; the manual does not describe an operator-set tire-pressure stop.
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Assessment scenario: 400P-AUTO trigger-gun vehicle-tire inflation
An assessment scenario for a suitable 12V direct-battery setup that prefers a trigger-operated gun and 30-foot hose. The fixed pump pressure switch is not a user-selected tire target stop; use the exact 40045 manual and check conflicting tire-size claims.
Explore this buying guide ↗Why consider this model?
- The exact 40045 page/manual identify a 12V dual-clamp arrangement with a 30A draw and 40A fuse.
- The package includes a 30-foot hose and trigger gun with gauge/bleeder valve for manual pressure management.
- The manual distinguishes a fixed 130/155-PSI pump pressure switch from the user’s tire-pressure target.
Tradeoffs to weigh
- The model is not documented for a vehicle accessory socket, cordless use or preset tire-pressure stopping.
- Its tire-size claims conflict: the product page says up to 37 inches while the table lists 35 inches.
- The 33%-at-100-PSI duty limit, hot fittings and hose care still matter.
Check these before ordering
- Verify SKU 40045 / 400P-AUTO (the product page also displays 400P-A), not 40043 or 40145.
- Confirm the 40A fuse, clamps, trigger gun, hose, tips and Presta adapter are included.
- Use the manual’s trigger procedure; release flow at the target, pause to check gauge pressure and remain present.