Vivitar Zoom Thyristor 2500 flash unit. This versatile auto flash unit has a zoom feature and adjustable angle head to allow ceiling bounced flash for a more natural lighting. It has 2 auto settings to allow different range/lens aperture combinations. This was my late father-in-law's which he hardly used so it's in almost as new condition. I have checked it as far as I can (without actually taking a photo) and it appears to to be fully functioning. Comes with a folding diffuser lens, soft case and instruction booklet.
eBay