Welcome to All Music Inc's Musicdungeon, you are looking at a great piece.  
This is the Supro Flanger Electric Guitar Effect Pedal.
Sibling to the Supro Chorus, the Supro Flanger is an all-analog, full-stereo modulation effects pedal that uses a quartet of genuine MN3009 Bucket Brigade IC chips to deliver the absolute richest Flanger effect possible while maintaining exceptional headroom. 
In addition to Speed and Width knobs, the Supro Flanger features a bi-directional Feedback control and a Sweep control that increases the delay time on one side of the stereo field while shortening the delay time on the other side. 
Featured for the first time in a flanger pedal, the Dimension switch crossfeeds the two channels into one another, creating the entrancing double-flanger effect of two delay lines being modulated in opposite directions, even when used in mono. 
Runs on standard 9VDC.
This Supro is in very very good condition as you can see in pics.
Tested and works as it should.
We were an authorized Supro dealer for over a decade.
Buy with confidence. 
Don't pass this by.