Kriegsmarine (sleeve badge)

[oliverzx6]

Hello,

is the sleeve badge a badge for "Sonderausbildung (special training)" or a "Laufbahnabzeichen (career badge)" ?
Is the size and the color the difference between the badges (i cant see it on the photo) and/or the arrangment of the wings on the grenade?
I ibly know the badge "Sonderausbildung" ist worn under the rank badge (but he wears none)

Thanks

Greetings Oliver