720s Monofilament Nylon Thread
Incredibly strong 720s weight Monofilament Nylon can still be used in a sewing machine but the intended use tends to be to add body to projects - i.e. adding weight to bridal wear hems.
Despite its weight 720s is incredibly unobtrusive and often referred to as invisible due to its translucent qualities which give it the ability to blend into the main fabric body.
Spools perform best used under a Dome & Base - a one-off purchase - to control the naturally slippery thread during sewing.