Here is a vintage Williams Foolproof  #CAR Receiver Peep Sight for Government 30 M1 Carbine. The Foolproof sight differs from the 5D in that is has internal micrometer adjustments for elevation and windage. "CAR" is marked on one arm of the sight (see photo). Screws and the original instruction sheet are provided.

Condition. It is in excellent condition and does not appear to have ever been mounted. There is some shelf wear to the box and it has a piece of tape on it.  A label not original to the box is stuck to one end. 

Maximum approximate dimensions: Width 1.8 inches (4.5 cm) Length 2.4 inches (6.1 cm) Depth 1.6 inches (4 cm).

PLEASE SEE PHOTOS FOR DETAIL AND CONDITION

THIS  ITEM SHIPS TO CANADA AND THE US ONLY

Item # T2783