Price is for 1 what appears to be a NOS preamp tube. This is very well known vacuum triode valve made in the mid-1960s by Siemens in Munich, West Germany. With gold pins, O-getter, double staged support and gray plates.
Stamped codes are A6 1B.
Tested STRONG as follow:
Ia1 = 14.0 mA | S1 = 12.4 mA/V | Ri1 = 2.9 kOhm | μ1 = 36.0
Ia2 = 16.1 mA | S2 = 11.4 mA/V | Ri2 = 3.0 kOhm | μ2 = 34.2
Tested at: Uf=6.3V, Ua=90V, Ug=-1.3V
Good starts at Ia=8.5mA and 100% is Ia=15.0mA
Shipping will be Airmail registered with tracing number. Other shipping methods available on request.