The Vox de Luxe tremolo was fitted to several early/mid 1960s solid-body Vox models with radiused fingerboards: the Ace, Super Ace, Escort, (early versions of the) Consort and Marauder. Note these are all UK-produced (JMI) models. Later Italian-built guitars did not use this part.
The chrome-plated De Luxe tremolo cover simply clips into place; two indentations on the cover sides fit into two holes on the bridge unit itself. Covers are engraved with the Vox logo and the words "PAT. APP. FOR" (patent applied for - this presumably relates to patent GB905447A, which describes a tremolo unit developed by Derek Underdown for Jennings, and applied for in August 1960). The saddles each hold two strings, and are forward/backward adjustable to set intonation, and height adjustable to set action. The bridge base unit is unplated, unlike the cover and tremolo arm. Early versions of the De Luxe tremolo were unsprung; this one merely had a piece of foam wedged between the top and bass unit, which may or may not be original. This model required no extra routing to the guitar body. From some time in late 1962/early 1963, De Luxe tremolos were improved somewhat by the addition of spring action, i.e. a spring was fitted to the underside of the unit providing some pressure against which to operate the vibrato. This required an extra route of the guitar body under the bridge. These bridges are easily detectable, without looking at the guitar body by the large grub screw going down through the tremolo in front of the saddles (center of image). Note also the cover mounting holes in the side of the bridge itself. The advert shown for this de luxe tremolo unit is from the British publication Melody Maker from November 1960 - this was available about the same time as the Vox Ace - the guitar shown in the advertisement.
List of Vox guitar tremolos