12 Spools SUMMER Embroidery Machine Thread 12 Spools SUMMER Embroidery Machine Thread This auction is for 12 Spools Of SUMMER Embroidery Machine Thread, It is 40 Weight Polyester. About Embroidex Threads, These Threads are of highest Quality. They are comparable to the threads you buy at your local dealer for $5-$6 a pc. We have put together kits and sell them for a quarter of the price.