Vintage Vivitar Auto Thyristor 225 Camera Flash (Tested) with Canon Hot Shoe

Warning: Not to be used with modern cameras due to risk of high trigger voltage damaging electronics.
 
The Vivitar Auto Thyristor 225, marketed through the late 1970s and early 1980s, is a shoe-mount flash designed for use with older mechanical film cameras. It features two automatic exposure modes based on color-coded settings, or it can be used in a manual mode for maximum light output. 
 
Ours has what we believe is a serial number 0024943 on the back. It is clearly used, with some residue on the side and back that we could not clean off, and tape from our mother with her OFF ON note to herself. But it does work as shown in the attached video. And the battery compartment is clean. Note: It needs two AA batteries, which are not included.
 
The slide-on single-pin Canon Japan hot shoe / flash coupler comes with it, as it was attached when we found the flash. It has no model number on it.
 
Disclaimer: We have tried to make sure colors shown in photos are representative of the real colors of each item. We have tried to identify all imperfections in descriptions, but we may have missed some. If you are unhappy with your purchase, let us know.