The 6K7GT pentode was designed in the mid to late 1930s for intermediate frequency amplifiers in 'modern' superhet type receivers. It is high impedance allowing for a high Q in the tuned anode circuit.
Watford Valves site has the following information on Fivre. Fivre was the largest all-Italian company, founded in 1932 in Pavia by Magneti Marelli to produce vacuum tubes under Radiotron (RCA) license.
See also the 6K7G full sized glass envelope version, and 6K7 original metal valve.
The perforated cylinder is the outer screen. The paper label contains the maker's logo but the black overprinting obscures the design.
The right side of the paper label.
The wide glass tube envelope is 28 mm in diameter and excluding the IO base pins the valve is 78 mm long.
References: Data-sheet & 1040. Type 6K7GT was first introduced in 1938. See also1938 adverts.