Extremely rare unit. 

Condition: This appears to be an early production Marconi PS No. 213A key (no markings on the side as with later keys).   The materials appear to be consistent with an authentic Marconi key.  There is quite a bit of green oxidation and corrosion on all the metal portions.  Leaving it up to the new owner to clean.  Underside was opened and is in good shape.  The bakelite knob has some wear consistent with use.  Bakelite base is in good shape with only some scratches on the underside.

Comes with: As pictured.

Shipping:  Items ship same business day (before mail cutoff).  Domestic shipments sent USPS Priority.  Optional USPS Express (1-2 day) service available at checkout.