This is a vintage round plastic sewing box or thread caddy, probably from the 1950s. Made from creamy off-white plastic (looks like celluloid but it isn't) it has a round domed lid that fits tight onto the base. Inside there are plastic spindles to hold 12 short spools of thread, attached foam rubber to hold pins and needles, and enough room for various sewing tools or notions. I've included an assortment of vintage wooden spools of thread. I use older thread like this for hand sewing, visible mending and fine hand embroidery on doll or baby clothing.
 
Pre-owned, genuine vintage. In great condition with no cracks or flaws.
 
Measures 7" diameter and is 2" tall.