Sparton Radio set.

[Old Sparky]

That type of P.B. mechanism was used on most makes of Car radios in the 50s, 60s, & 70s - usually called 'Prestolock'. A variation called 'Prestotune' used mainly by Philips, Pye & Ekco, in which eac individual button was tuned to the required station, was also produced, but I didn't know that such mechanisms had ever been usefd in domestic radios, nor with variable capacitance tuning. Most car radios emplyed permeability tuning in which the inductance was varied, and the capacitance fixed. Some Philips and Blaupunkt Car radios used a more complex version of the Prestolock tuning mechanism which had Eight pre-sets.