recessed retainers 49 and plural tabs 47 48 in this embodiment the recessed retainer has a distal region with an inner width e that is narrower than the width f of the proximal region each tab is defined by two prongs however the prongs of the tabs are different the tab 47 is defined by two inwardly extending prongs which tabs also define a recessed retainer 49 having an inner distal width d the tab 47 comprises a proximal region 47 b which width is narrower than the corresponding distal region 47 a accordingly in one embodiment a tab also serves as a recessed retainer since the prongs that define the tab also define a recessed retainer embedded within the tab the tab 48 comprises two outwardly extending tabs having a wider g distal region 48 a and a narrower h proximal region 48 b the tab 48 is adapted to be retained by the recessed retainer 49 defined by the periphery of the connector and or the prongs of the tab since two adjacent prongs can define a tab two adjacent smaller apertures can define a recessed retainer for example the pair of adjacent apertures 51 in the connector 45 is adapted to interlock with the pair prongs of the tab 47 and or 48 from another connector the farthest most edges of the apertures would then define the widest width of a slot according to.