Baby Lock 8MM Knit/Woven Double Fold Bias Binder - Double Fold Bias Binder Knit/Woven - 8mm (BLCS-DFBB8) This double fold bias binder will turn fabric strips into binding and attach it to project edges all in one step. This attachment is exclusively for the Coverstitch, and is perfect for curved edges, collars, and necklines on knit or woven fabrics.