"Hand-decorated glass with ceramic colors melted at 650ºC." Their website has gone but the site is archived
here.
Their crystal seems to have been either decorated bottles or sets of bottles and glasses like yours. The website said the company was founded in the 1960s, its website disappeared in 2012/3.
This site gives its description as
"Company main activity
SIC: 5023 - Home furnishings
CNAE: 5144 - Wholesale of china and glassware, wallpaper and cleaning materials"