A reactive polysaccharide derivative of formula, Z1\u2014B\u2014SO2\u2014CH2\u2014CH2\u2014On\u2014PS\u2014OHm, wherein 8 is a radical of formula, ,, or, Z, is a reactive radical, and PS is a cyclodextrin, is useful as a finishing agent for textile fibers and for other applications. At least one bristle can be attached to the head. In addition, the weight member provides a damping force to the user’ arms so as to exercise the user’s arms. The polyols are suitable for use in the production of isocyanate casting resins and coating compounds with enhanced colour stability.