{{tag>collection_mcmaster vendor_bell type_mask year_unknown foundry_unknown tech_unknown}}

====== Source ======

eBay seller toober.  They claimed its from Bell Labs, I have no way to verify that.


====== Overview ======

{{:mcmaster:bell:bth-mh_mask:overview.jpg?300}}
{{:mcmaster:bell:bth-mh_mask:case.jpg?300}}

Markings
  M145705-17-01 M3T45
  PM000000
  BTL-MH
  
  28
====== Mask ======

{{:mcmaster:bell:bth-mh_mask:lesser_mit2x.jpg?300}}
{{:mcmaster:bell:bth-mh_mask:main_mit2x.jpg?300}}