This excerpt taken from the GWW 10-Q filed Aug 2, 2006.
9.2 Value of Performance Shares/Performance Units. Each Performance Share shall have an initial value equal to the Fair Market Value of a Share as of the date of grant. Each Performance Unit shall have an initial value that is established by the Committee at the time of grant (for example, the Committee could grant 10,000 units to a participant and determine their value at $1.00 per unit). The Committee shall set performance goals in its discretion which, depending on the extent to which they are met, will determine the number and/or value of Performance Shares/Performance Units that will be paid out to the Participant.