Elgin Grade 212

This is a less common Elgin pocketwatch movement. It's a grade 212, 16 size, 7 jewels, made about 1904. 

The secondary serial number stamps on the major parts are prefixed with an 'X'.

This is a "Swing-out" case. There is no removable back. Instead the movement is mounted in a hinged ring that comes out from the front. Few joints in the case mean less dust getting inside.