The addition "Prov" means "test" - so it is a single piece, not from a series. Other glassworks use the word Unik or Unikat for that.
The piece is made an designed by Hanne, who is married to Arthur and uses both names.
I'm not sure if Hanne's work is being avidly collected, but in itself this is a fabulous piece of Swedish art glass, signed et all, by one of the most achieved glass artists in the country. Hanne was originally from Germany and worked for Maleras, Flygsfors and Kosta before she went to Studio Glashyttan in Ahus in 1977.