Pfaff twin welting foot cat k the pfaff welting foot and the twin welting foot are used to make rim for your home dec projects like pillows cushions and other home accessories you can also make trim cover raw edges on your upholstery which you can then attatch with a staple gun its quick and easy to make and insert welt cording the welting foot works the same way as the piping foot but is designed for larger sizes of cording create your own trim when the colour you want isnt available