Delta is a Russian clone of ZX Spectrum+ manufactured in 1991 on a former-military plant near the city of Zelenograd. It's fully compatible with Spectrum+. Comes with 48K RAM and it have video output, power input, cassete in/out, two joysticks ports (Kempston and Sinclair), reset button, RGB adjust and its own expansion port for Russian hardware.

Possibly related to Delta S-128 .