Assertion: pen's button | /r/HasProperty | single
Facets:
Source sentences:
text: Many vape pens have a single button used for all controls, including on/off functionality and temperature adjustment, while others have no button on all and work with sensors which react when the pen is in use.
text: Tabletop and portable vaporizers typically have an on/off button that must be manually turned on and off, while vape pens feature a single button that you press to turn/stay on and release to turn off.