The vintage Russian
K40Y-9 capacitors in this precisely matched pair are high quality PIO
(Paper in Oil) types made for the Soviet military. They have
glass-sealed aluminum foil conductors and oil saturated paper
dielectrics in a metal bodies--similar in construction and performance
to the more expensive Sprague Vitamin Q capacitors. Great for improving
guitar tone or for use in high-end audio applications.
These
capacitors are unused, straight from the factory packaging. They have
been checked on two capacitance testers and then run in a custom fixture
to check for leakage at 1000V. They are matched within 1% of each other
and within 5% of the rated capacitance.