Good day -
This 3.75" diameter B&W Faraday link #3781 is to couple a large tank coil to an antenna, or tuner. It's Faraday design works to reduce the capacitive coupling of harmonics.
It's used, but seemingly in good order.
It's on its way to your CONUS hamshack when you send $30. to my Paypal account with an address of "al@w8vr.org."
Thanks es 73.
-al hart
al@w8vr.org www.w8vr.org