It seems to be used for measuring impedance across three faces.
Onthe back of it states that this item was made in Poland.
TheQC stamp markings show number 66 which is probably the year of manufacture, although there is also a 1988 on it, unsure whether this is a year or a serial number.
It’s untested.
Vintage Impedance Box P-1 Made In Poland 1966? 1988? Made For Phasemetee LF-1. Condition is "Used". Dispatched with Royal Mail 2nd Class.
