The plastic ring, new to the market, not only had a much longer life than the PW steel ring but also apparently had a much lower manufacturing cost. Thorborg's problem stemmed from PwI's large quantity of steel rings on hand and the substantial inventory of special steel that had been purchased for their manufacture. After a thorough survey he had found that the special steel could not be sold, even for scrap: the total book value of these inventories exceeded $390,000