The snap distance between the two buttons is 40mm/1.57'' and size of the button is 3.5mm(see picture 2 for reference), pls confirm and check the snap distance of your unit before ordering to avoid ordering the wrong size 10Pcs Pads for Whole Body Massager, 3.5mm Button Size, 1.57‘’/40mm Distance, Pad Only (Host is not Included)