I bought one for my Viking and ended up returning it. As someone else said - a 'very generous' 1/4". I thought it would help me keep a straighter seam at the beginning and end but no such luck. My machine has a 'scant' 1/4" setting with a standard foot and that works a charm for me. For the other machines I have and/or had - the metal 1/4" foot without the flange worked just fine as well. Guess it's all what you get used to.