Or from Latin baculum a stick, because the squire would practice with a staff, not a sword. Meaning evolved from knight in training to young unmarried man (early 14c.). Bachelor party as a pre-wedding ritual is from 1882.
A transcutaneous electrical nerve stimulation (TENS) unit is a device that sends small electrical currents to targeted body parts. These currents are used to relieve pain. Some TENS units are designed for use in a hospital or healthcare facility.
Compared to a TENS machine, EMS neuromuscular stimulation treats more of the muscle area than the nerves. The unit can be used to reduce pain, spasms, and swelling, while promoting healing and strengthening injured muscles. The PM-555 EMS Digital uses dual isolated channels to deliver the wave signal efficiently.