W.E. headset - speaking tube receiver?

[unbeldi]

I tested the resistance with a digital ohm meter and got a reading of 669 ohms. That closely matches the number stamped on the receiver of 650.

669 ohms is awfully high for a receiver element for any telephone. In comparison, an HA1 receiver has a DC resistance of ca. 26 ohms, and an HA2 of 57 ohms.  A 144 receiver used an element of ca. 80 ohms, by my measurement, although the catalog states 33, I believe.  I think these are stamped 75Z on the magnet.

Where on the receiver is that number stamped? On any of the magnet part or on the case?
Is the number accompanied with the letter Z ?

With a resistance this high, this receiver must have been used as an additional monitor receiver in multiple with a standard type telephone receiver. Since it has a switchboard plug it must have been used in the central office or with test equipment.
The NO. 146A (46A?) receiver had a resistance of 640 ohms, per catalog 1935, and it also had the shape of yours.
I think this is what it probably is.

[wds]

pic of mine, and another one that sold.

[Stubbypylon]

My speaking tube receiver only has the number of 11139 on the back and a resistance of 5.5 ohms.

[unbeldi]

The 1923 catalog lists the 146AW receiver as having a resistance of 650 ohms.

In the 1916 catalog the 146A doesn't exist yet, but the 146W has a resistance of 610 ohms.
The 146 line of receivers is the only one with such high resistance. If your measurement is correct, then it has to be this kind, I believe.

The 144AW is listed with a resistance of 75 Ω.

I think the 1916 catalog is the only one that shows this type of head band consisting of a single wide strip of metal.

[wds]

Here are the pages out of the 1916  cat. that you refer to.  I see no reason why this receiver on this head band couldn't be authentic and original. 

[unbeldi]

Here are the pages out of the 1916  cat. that you refer to.  I see no reason why this receiver on this head band couldn't be authentic and original.

I agree, seems fine.  The type of head band in the catalogs is just an example, IMHO. Various receivers or receiver holders could be used with several of the head bands.