This is one of the rare F300hz models that is more discretely marked with Electronic on the dial rather than F300hz!
 
The F300hz (known as a hummer as its dual tuning forks hum) is a movement made on license from Bulova watches. It predated the quartz watches and was a quantum leap forward in performance compared to mechanical watches.
 
This is the top-of-the-range Constellation model that has a hewn from a block of steel feel. Modestly sized at 32mm but solid. The silver dial is almost unmarked. The applied hour batons are polished steel as is the Omega logo. Signed Omega, Electronic, Chronometer, Constellation and Swiss Made. Black stick hands and sweep seconds hand. 
 
The case and case back are brushed stainless steel and are almost unmarked. The lugs are integrated so the watch wears larger on the wrist than it otherwise would. 
 
Inside is the Omega 1250 movement made under license from Bulova. You can see the twin-tuning forks in the picture. It is powered by an inexpensive battery that is readily available.
 
Attached to the watch is an Omega stainless steel bracelet in excellent condition. It should fit a medium-sized wrist and comes with two spare links.
 
The Constellation is a top-of-the-range Omega model and this rare (non-marked F300hz) is representative of a short but significant part of Omega history.