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.
However, some new research has shown that TENS may be effective for reducing pain in people who have fibromyalgia, especially in combination with other treatments, such as exercise. Fibromyalgia is often treated with various medications to relieve pain and improve sleep.