The piping foot will have its limitations when using thicker piping including the heavy jumbo cord and this is when the adjustable zipper foot will be invaluable. A screw on type foot, it can be adjusted to fit snugly against the cord when covering your own piping or when attaching commercial piping.
Janome Adjustable Zipper Foot/Piping Foot
Cat A - 2200XT, 2300XT, 423S, J3 - 18, J3 - 20, J3 - 24
Cat B - 525S, CXL301, DKS30, DKS100, DXL603, HD2200, QXL605, TXL607, XL601, M50QDC, M100QDC, M200QDC, 725S, 230DC, 740DC, 780DC, 4300QDC, 360DC, 5060QDC, 5270QDC
Cat C - Atelier 3, MC7700QCP, MC6600P
Cat D - Atelier 5, Atelier 6, Atelier 7, Atelier 9, MC15000, MC14000, MC12000, MC9450, MC9400, MC9900, MC9850, MC8900, MC8200, MC6700P, Continental M7P