This style is the middle size in the "600" series, between the 680 (CD 221) and the 660 (CD 218 and 219).
4 1/4" H x 3 3/4" W
• HEMINGRAY • NO EMBOSSING
Rarity Scale (1-10):
Primary Power Distribution
Small Saddle Ridge Variant
This is the  mold variation, which has a smaller wire ridge, a more pinched saddle groove running from front to back (perpendicular to the embossing) and is also 1/8" taller. The embossing is also the newer, small stamped style. This mold appears to only have been made in 1947.
Personally, I feel this mold variation is significant enough to warrant its own CD number (such as 220.1).
Locke Hi-Top Style Variant
This is the CD 220 No Embossing , Locke Hi-Top Style variant. It is believed to have been manufactured by Hemingray, and was most likely a dump specimen. There are two distinguishing features of the Locke Hi-Top style: the top wire ridge has an extra "step" and the ears are flatter. Photo courtesy of Bill Meier.