The picture shows a view of this Old Unused Midwest Coil & Transformer Company Advertising Premium Key Chain. This keychain or keyring is not dated but it is old. The maker is unknown. The right side ring is detachable by squeezing a part. The key chain appears to be made of brass and in the center is a red painted company logo. It is marked as follows:
MID-WEST COIL & TRANSFORMER CO.
The keychain measures 4'' long. It appears to be in mint unused condition as pictured.