US WWI AND WWII Insignia

Us military insignia. Pic 1 is a small assortmant of items I purchased yrs ago. Pic 2 is A WW II Crossed Cannons Collar disc. Pic 3 is a WWI bronze US collar Disc. Pic Pic 4 is a WWII brass collar disc. Pic 2,3,&4 have screw backs .Others in the frame include a US Calvary hat pin WW I, a WWI US Army Air Prop Wing , A Korean issued Service pin, A German Nazi RAD service pin. RAD prepared youth for transition into the military. Very bottom is a bronze button marked Superior Quality. It was with the military items and I assume it is a uniform button but can find no info on it. Image on it is a Y shape extending thru a ring. Can't hilite these because of poor images. Enjoy and thanks for viewing and commenting.