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Offer to Purchase for Cash
All Outstanding Shares of Common Stock
$10.50 Net Per Share
Ventura Acquisition Corporation
a wholly-owned subsidiary of
September 10, 2010
To Our Clients:
Enclosed for your information is an Offer to Purchase, dated September 10, 2010 (the " Offer to Purchase "), and the related
Letter of Transmittal (which, together with any amendments or supplements thereto, collectively constitute the " Offer "),
relating to the offer by Ventura Acquisition Corporation, a Delaware corporation (" Purchaser ") and a direct wholly-owned
subsidiary of 3M Company, a Delaware corporation (" 3M "), to purchase all outstanding shares of common stock, par value
$0.001 (the " Shares "), of Cogent, Inc., a Delaware corporation (" Cogent "), at a price of $10.50 per Share, net to the seller in
cash, without interest thereon and less any required withholding taxes, upon the terms and subject to the conditions set forth in
We are the holder of record of Shares held by us for your account. A tender of such Shares can be made only by us as the
holder of record and pursuant to your instructions. The Letter of Transmittal accompanying this letter is furnished to you for
your information only and cannot be used by you to tender Shares held by us for your account.
We request instructions as to whether you wish to tender any or all of the Shares held by us for your account, pursuant to
the terms and conditions set forth in the Offer.
Your attention is directed to the following:
The offer price is $10.50 per Share, net to the seller in cash, without interest thereon and less any required
withholding taxes, upon the terms and subject to the conditions of the Offer.
The Offer is being made for all outstanding Shares.
The Offer is not subject to any financing condition. The Offer is cond