Unknown WW2 1941 Dated Boxed Electrical Component

I have not been able to sort out what this item is, my best guess is something for a radio and is used to conduct a current, It has 8 metal pins for plugging in separated by 3 layers of Bakelite, two central cylinders that are marked with a series of numbers and various metal plates and wires. It is well marked with impressed numbers and letters including what I am taking as the date of '41, printed it has T. rls. 43a in black and in red 2 August 1941. It comes in its original box, the piece measures 4 inches long and is in excellent condition the box having signs of age.