This scale has never been removed from its box and is still in its original packing with protective plastic over all appropriate surfaces.  It belonged to my late son-in-law, who never used it, and I was asked by my daughter to sell it.  Never having used one, I'm ignorant about this sort of scale, but an enclosed instruction booklet, published in 2006, has provided specifications (see photo) and the following summarized information:  
Please get in touch with questions.  I'll do my best to answer them.