How to change Parasym settings
Following a few questions about changing the settings on a parasym, Andrea Parker OT has very kindly done us a brief video showing how. (Her explanation of polyvagal theory and TVNS video is under files) Parasym is set to 20htz and 200us originally. Lots of people do very well with these settings.
Please note, these are the most gentle settings for beginners;
50us
20htz
1 minute
0.8ma
These are generally better tolerated 
Some parasyms may be locked to your settings. If this is the case you may need to contact parasym themselves. Please do let us know how it’s done with a locked device if you find out 