Following the V232, Vox debuted the V250, a hollow-body bass based on the Eko 995/2. While it shared much of the Eko's DNA, the V250 swapped the 995/2’s scrolled headstock for the signature Vox 'paddle' design and was offered by Vox in 1966 and 1967.

Next came the Vox Astro IV, first appearing in the 1967 US Vox catalog. Like its predecessors, it was produced by Eko in Italy. This model stood out for its unique battery-operated electronics and was a staple of the US Vox catalogs in 1967 and 1968.

Vox followed in 1968 with their final violin shaped bass, the V283 Spyder. The Spyder was essentially the V273 Astro IV bass in a passive format without the battery powered onboard effects.

The 1968 US Vox catalog described the Astro IV bass as follows: "An electric acoustic bass guitar with the popular violin shape body. Has built in G tuner, distortion booster, treble and bass booster. All new easy-to-fret fast-neck with the Vox double T-bar and adjustable steel rod. Has two exclusive VOX Ferro-Sonic pickups. Fully adjustable bridge. One volume, two tone controls, 3-position pickup selector switch. Has jumbo chrome plated machine heads. Sunburst, Cherry, or Sandburst."

The Astro IV Bass was a short (29.5") scale instrument featuring a 21 fret bolt-on neck with an exceptionally slim profile. At the aluminum nut, the neck measured just 1.4" wide by 0.7" deep and 1.75" wide by 0.875" deep at the 12th fret.

Retaining the signature Vox look, the Astro IV featured a paddle shaped headstock adorned with a raised gold-plated logo and jumbo tuning machines.

Internally, the neck was stabilized by the Vox "Double T" aluminum extrusion and included an adjustable truss rod for fine-tuning neck relief.

Similar to the Hofner 500/1 "Beatle Bass," the Astro IV featured a hollow, semi-acoustic laminated body. The Astro IV  measured 13.25" wide at the lower bout, 1.875" deep, and 19.5" long. Average weight for an Astro IV was ~7 lbs. In contrast to the Hofner 500/1, the Astro IV was designed with a pair of fully bound split f-holes.

Beyond its built-in battery-powered effects suite, the Astro IV was equipped with two single-coil ferrite magnet pickups with exposed pole pieces, a chrome-plated cast tailpiece and a micro-adjustable floating bridge that featured a rosewood base and a chrome plated steel cover.

The 1968 US Vox price list indicated that the retail price of the Astro IV was $395 USD. In today's dollars, the Astro IV would have retailed for about $2500.

The Astro IV Bass was produced for Vox in Italy by EKO in Recanati Italy. A decal on the back of each bass states: "Made in Italy by Vox."