Patriotic Shield Drum Head Tensioning Device
Described by eBay seller georgiadigger( 348) as follows:
Brass patriotic shield, drum head tensioning device. Similar to one pictured on page 39 of Howard Crouch's "Civil War Artifacts, A Guide for the Historian".
This was eBay item no. 130247758735, purchased by deo*vindice( 858) for $50.03 (outbidding me by 3 cents -- congratulations).