[Letterhead]
November 9, 2011
Securities and Exchange Commission
100 F Street, N.E.
Washington, D.C. 20549-7561
Commissioners:
We have read SG Blocks, Inc.'s (fka CDSI Holding, Inc.) statements included under Item 4.01 of its Form 8-K dated November 4, 2011, and we agree with such statements concerning our firm.
/s/ Becher Della Torre Gitto & Company PC