What is American Anti Auto Thief Association? Need an automotive history buff

I found this with my metal detector. Can you take a look at it and tell me what it is?

The writing is as folows: American Anti Auto Thief Assn 1927-28 Registered Automobile Inc.

I would appreciate any help you guys could give me figuring out what this thing is.

I look forward to hearing from you soon.

Sincerely,

Jim Rudisill

Can Anyone Help? Let Me Know...msnide@theautochannel.com