The Epiphone 5120 bass was made from 1970-1971, in by the Japanese Matsumoku company. The Epiphone 5120 had an ES-335 style hollow body, twin pickups with dual controls, deluxe heavily chrome-plated machine heads. Sunburst finish on the front and back with an adjustable maple neck. Rosewood fingerboard with offset pearloid dot position markers. Chrome plated adjustable bridge wtih a custom desgined spring type mute. Trapeze trail-piece with wooden insert. This model was identical to the Aria 5120 bass - both were made in the same Matsumoku factory. The Epiphone versions had cherry red finish, the Arias are sunburst.  This model was renamed/replaced by the EA-260 model in 1972.

Epiphone described the 5120 bass as follows in their 1971 catalog:

5120: Here's a hollow-body electric bass that is the ideal companion for the new 5120T guitar. True bass-pitch response throughout its tonal range.

Features: Double-cutaway thin body with multiple binding. Select hardwood top, rims and back. Twin pickups with adustable pole-pieces, toggle switch. High gloss cherry red finish, slim, fast, low-action three piece adjustable neck, rosewood fingerboard with pearl dot inlays, adjustable precision bridge, custom designed mute, deluxe machine heads, chrome plated parts. 15.75" wide, 18.75" long, 1.9" thin; 30.5" scale length, 20 frets.
 

Source: Epiphone 1971 catalog.