A coupler including an annular body having an annular body outer surface and an annular body inner surface connecting opposed annular body first and second faces, the annular body inner surface bounding an internal opening communicating between the opposed annular body first and second faces; the annular body having opposed annular body first and second ends which connect the annular body outer and inner surfaces and the annular body first and second faces to define a radial slot which communicates with the internal opening; the annular body sufficiently resiliently flexible to provide an adjustable radial slot width of the radial slot; and a plurality of spaced apart teeth radially inwardly projecting from the annular body inner surface.