Polish lantern from sixties for 2 250W MV lamps, here dayburning with a 210W HPS with Penning mixture retrofit lamp.
There were several ways of naming Polish fixtures, interesingly they were almost in every case an acronym.
ORZ-X - Oprawa rtęciowa zewnętrzna - External Mercury Fixture, X stand for the next developed model, so ORZ-1 was first in series, ORZ-2 second etc...
OUR-X - Oprawa uliczna rtęciowa - Street Mercury Fixture, X stand for power of MV lamp, in case of fixture with two lamps it is 2xX or 2X.
OUS-X - Oprawa uliczna sodowa - Street Sodium Fixture, same as above but for HPS lamps
OURW-X - Oprawa Uliczna Rtęciowa z Wewnętrznym osprzętem - Street Mercury Fixture with internal gear, specific series of fixtures where lamp housing module and gear housing module were made separately and later in production connected together. X stand for the same as in OUR-X fixtures (the only exception is OURW375 which is for 125W and 250W lamps).