Univox Stage 65 speaker replacement

[gbazinet]

Sorry I know this is a guitar amp but i couldn't find anything through a quick google search so though i would try here.

I scored a Univox/Unicord Stage 65 combo amp for free today with a 12 inch speaker that i am 90% sure is blown. I am going to replace the speaker but cant seem to figure out the OHMS rating. Anyone have any info on this or can point me in the right direction?

[gbazinet]

Seems to me that this amp is pretty much the same as these:

Model 65 Combo - 20W, 12" speaker, volume, bass, treble, clipping control and reverb.

Model 65B head and cabinet, 12" speaker, 2 inputs, volume,bass, treble, "speaker" and "line out" on back.

Model 252 Bass Combo - 20W 15" speaker,volume, bass, treble.