If you want to see precisely how much galvanic current you are using, you can purchase an external milliamp meter, The meter itself is larger than found on any machine. It uses banana jacks. Connect the meter to the inactive (hand-held) jack on the machine, then plug the inactive electrode into the meter:
https://www.schoolspecialty.com/frey-scientific-dc-milliammeter-0-1-ma-1477772?gclid=CjwKCAiAlb_fBRBHEiwAzMeEdqJP_Rxk5BjDW0q8WRT9pWxkVbyqbmMV2db1LK5_CA5fN0IjiOrssxoCeIoQAvD_BwE