old altimeter help please?

hey all i just picked up this old altimeter called 'ultimeter' , model 8, made by the peet bros. company. i can't figure out how to set it. it has 8 buttons on the front panel labeled altim, barom, temp, hi-low, enter, metric, cal, timer. when you put the batteries in it displays 12:00 with a flashing colon (something i've always dreamed of) and it appears to shut itself off after a period of inactivity. anyone remember how to set these buggers up?

I fooled around with one of those years ago, and decided it was better as a wheel chock. Don't remember how to set it though... Dan M