The truth is you cannot be sure, there were many companies that made this Stretch Style Vase in the 60's, it was the era of the Art Glass. Many glass blowers on the Island of Murano Italy made these as well as American Companies such as Blenko Glass and a few others that did not become well known or stay in business long. A lot of local artists in areas also made these, they sold them at local art fairs, and shops.
So there is no way to know who made it but, it can be valued. Over the years, ( 45 ) I have bought, sold and appraised vases like this many times. So I can give you a value for this and what they are currently selling for on today's market. If you like?