The "Uhtua front" badge (it's widely known that 3.Division which had defended Sahakylä - Kuuterselkä area in June 1944 had fought in Uhtua (now Kalevala) during 1941-1943). It was possibly silvered. It was fixed on the uniform with iron screw-nut (partly could be seen on the photo).
The ruler scale is in centimeters.
Thanks for information on the badge: Jarkko Vihavainen, Finland