I've got a box of them, and I just unwrapped one, to see what's in it. They are made by Strato Quality Railroad Products. A "Certificate of Compliance" comes in each individually wrapped gauge package. It carries Strato PN S182. The certificate also lists the build date, certified calibration, calibration interval schedule, descrition and tolerance figures. It has a rubber clad indicator, to help absorb impact, and they probably weigh around a pound.
I also have a few "carmans inline BP testers", which is a smaller gauge, with a flat needle, like a basketball needle, but mashed flat, for insertion between two coupled hoses, to verify BP at the connection, without disconnecting the trainline. This would not be suitable for the class-1 test, as the device needs to be mounted at the rear of the end of train. Send me a PM, I might be able to let one of mine go, at a VERY reasonable rate ..........
BTW, calibration for these, as in all devices measuring air pressure, calls for a scheduled time of testing, and verification of accuracy, of 3# or less, in variation between the source, and the measuring device. Calibration of this item, is effected by the user, by attaching the device to the front of a locomotive, opening the trainline, and verifying the measurement is within 3# of the EQ/BP settings. You should record this date on the gauge itself, or on a card you ALWAYS carry, in case documentation is requested, by your boss, or the Feds........