APG PG5-500.00-PSIG-f1-l4-N1-e23 549015-1356 PSI Digital Pressure Gauge.

Unit does not come with a power cord. This used a power cable only and not a battery.

Im not familiar with these things but it powers on and seems to work.  I blew on it and the numbers when up. You can see it in the pictures . Im seimg it "as is" since im not sure on how to properly test it.