A flemish string is 2 to 3 bundles of equal number of strands of a string material and twisted together to make the string.Usally different colors,looks like a barber pole.An endless loop is usally one continous strand of a string material run around a jig and then both loop ends are served.A flemish string is usally quieter and just looks more traditional to me.An endlles loop some say is alittle faster but noisier.This has been debated alot.Flemish twist and endless can be made from any string material,they are just methods for making strings.A flemish you can make without a jig,but a jig just makes it easier to measure the string length and stagger the ends before you start tiwsting.An endless you will need an endless jig to make,so you can serve the ends and make it to the proper length.