Jansen Spectroscopes

Jansen Spectroscopes is a piece of headgear which can only be worn by Jan Jansen, a potential companion in Baldur's Gate II: Shadows of Amn and Baldur's Gate II: Enhanced Edition, as long as he has at least 17 dexterity. It raises disarm&find traps with 25%, detect illusion with 20% and they can be used once per day to detect invisible creatures. Jan has this item equipped when he joins the party.

In-game description
"Jansen-Brand Micro-Macro Spectroscopes - (Official Spectroscopes of the Purple Brotherhood)

Another one of Jan Jansen's inventions, these glasses allow Jan to detect invisibility once per day. They also give Jan an additional +25% to his detect and disarm traps abilities. Various lenses on the contraption increase Jan's ability to detect illusions by 20%. The style of the Spectroscopes is so obvious it hardly needs to be mentioned."