Vintage M-133/U Dynamic Microphone US Military for MS22001 Oxygen Mask For Sale

Up for sale here is this M-133/U dynamic microphone. It is marked "MFR. 59369" on one area and "Microphone Dynamic M-133/U Front" on another area. I believe this is a microphone with a mount, for a military oxygen flight mask (specifically the MS22001 mask), but I am not 100% certain. This is untested but should work fine. I found some specs for this online:Frequency 200-50,000 HzSensitivity 2.5-5 mVImpedance 5 ohms +/- 1 ohmAltitude Compensation 50,000 feetTemperature -54 C - 55 CPer Mil Spec MIL-M-55516NSN 5965-00-900-8102
Please see my pictures for details.
US shipping and handling is $5, and international is $18, no matter how many you buy. If you have any questions, please ask.I have a number of other vintage parts, collectibles, Magic cards, and vintage electronics listed--feel free to take a look!