This is a Rectify Series drop-in speaker system for Walthers Proto and late Life-Like P2K SD45 locomotives using the 28mm round speaker encased within two weight halves held together by screws. No modifications are required to replace the factory speaker.
 
The speaker fits in the stock cavity, firing down through the frame. The loose half of the weight is discarded. Use a strip of double-sided carpet tape over the top and stick the enclosure into the cavity.
 
The speaker comes fully assembled and tested.
 
Dimensions are: 16mmH x 15mmW x 28mmDia