Exhibit 10.10

                                 PROMISSORY NOTE

$23,790.82                                                   As of May 1st, 2006

Vector Intersect Security Acquisition Corp. (the "Maker") promises to pay to the
order of SCP Private Equity Management Company, LLC (the "Payee") the principal
sum of Twenty Three Thousand Seven Hundred Ninety Dollars and Eighty Two Cents
($23,790.82) in lawful money of the United States of America, together with
interest on the unpaid principal balance of this Note, on the terms and
conditions described below.

         1. Principal. The principal balance outstanding under this Note shall
be payable no later than the first anniversary of the initial public offering
(the "IPO") of the Maker, provided that if the IPO does not take place by
November 30, 2007, such principal balance shall be payable no later than
December 31, 2007.

         2. Interest. Interest shall accrue at the rate of 5.5% annually
(non-compounded) on the unpaid principal balance of this Note from the date
hereof until it is repaid in full. In the absence of an Event of Default
hereunder, all such interest shall be paid not later than the date on which the
principal balance hereunder is due in accordance with paragraph 1 above.

         3. Repayment/Application of Payments. This Note may be voluntarily
repaid at any time without premium or penalty. All payments under this Note
shall be applied first to payment in full of any costs incurred in the
collection of any sum due under this Note, including (without limitation)
reasonable attorneys' fees, then to the payment of any accrued but unpaid
interest and finally to the reduction of the unpaid principal balance of this
Note.

         4. Events of Default. The following shall constitute Events of Default:

              (a) Failure to Make Required Payments. Failure by Maker to pay the
principal of or accrued interest on this Note within five (5) business days
following the date when due.

              (b) Voluntary Bankruptcy, Etc. The commencement by Maker of a
voluntary case under the Federal Bankruptcy Code, as now constituted or
hereafter amended, or any other applicable federal or state bankruptcy,
insolvency, reorganization, rehabilitation or other similar law, or the consent
by it to the appointment of or taking possession by a receiver, liquidator,
assignee, trustee, custodian, sequestrator (or other similar official) of Maker
or for any substantial part of its property, or the making by it of any
assignment for the benefit of creditors, or the failure of Maker generally to
pay its debts as such debts become due, or the taking of corporate action by
Maker in furtherance of any of the foregoing.

              (c) Involuntary Bankruptcy, Etc. The entry of a decree or order
for relief by a court having jurisdiction in the premises in respect of maker in
an involuntary case under the Federal Bankruptcy Code, as now or hereafter
constituted, or any other applicable federal or state bankruptcy, insolvency or
other similar law, or appointing a receiver, liquidator, assignee, custodian,
trustee, sequestrator (or similar official) of Maker or for any substantial part
of its



property, or ordering the winding-up or liquidation of the affairs of Maker, and
the continuance of any such decree or order unstayed and in effect for a period
of 60 consecutive days.

         5. Remedies.

              (a) Upon the occurrence of an Event of Default specified in
Section 4(a), Payee may, by written notice to Maker, declare this Note to be due
and payable, whereupon the principal amount of this Note, and all other amounts
payable thereunder, shall become immediately due and payable without
presentment, demand, protest or other notice of any kind, all of which are
hereby expressly waived, anything contained herein or in the documents
evidencing the same to the contrary notwithstanding.

              (b) Upon the occurrence of an Event of Default specified in
Sections 4(b) and 4(c), the unpaid principal balance of, and all other sums
payable with regard to, this Note shall automatically and immediately become due
and payable, in all cases without any action on the part of Payee.

         6. Waivers. Maker and all endorsers and guarantors of, and sureties
for, this Note waive presentment for payment, demand, notice of dishonor,
protest, and notice of protest with regard to the Note, all errors, defects and
imperfections in any proceedings instituted by Payee under the terms of this
Note, and all benefits that might accrue to Maker by virtue of any present or
future laws exempting any property, real or personal, or any part of the
proceeds arising from any sale of any such property, from attachment, levy or
sale under execution, or providing for any stay of execution, exemption from
civil process, or extension of time for payment; and Maker agrees that any real
estate that may be levied upon pursuant to a judgment obtained by virtue hereof,
on any writ of execution issued hereon, may be sold upon any such writ in whole
or in part in any order desired by Payee.

         7. Unconditional Liability. Maker hereby waives all notices in
connection with the delivery, acceptance, performance, default, or enforcement
of the payment of this Note, and agrees that its liability shall be
unconditional, without regard to the liability of any other party, and shall not
be affected in any manner by any indulgence, extension of time, renewal, waiver
or modification granted or consented to by Payee, and consents to any and all
extensions of time, renewals, waivers, or modifications that may be granted by
Payee with respect to the payment or other provisions of this Note, and agrees
that additional makers, endorsers, guarantors, or sureties may become parties
hereto without notice to them or affecting their liability hereunder.

         8. Notices. Any notice called for hereunder shall be deemed properly
given if (i) sent by certified mail, return receipt requested, (ii) personally
delivered, (iii) dispatched by any form of private or governmental express mail
or delivery service providing receipted delivery, (iv) sent by telefacsimile or
(v) sent by e-mail, to the following addresses or to such other address as
either party may designate by notice in accordance with this Section:

If to Maker:

Vector Intersect Security Acquisition Corp.
65 Challenger Road



Ridgefield Park, NJ 07660
Attn.:  Yaron Eitan

If to Payee:

SCP Private Equity Management Company, LLC
1200 Liberty Ridge Drive
Wayne, PA 19087
Attn:  Charles Freyer

Notice shall be deemed given on the earlier of (i) actual receipt by the
receiving party, (ii) the date shown on a telefacsimile transmission
confirmation, (iii) the date on which an e-mail transmission was received by the
receiving party's on-line access provider (iv) the date reflected on a signed
delivery receipt, or (vi) two (2) Business Days following tender of delivery or
dispatch by express mail or delivery service.

         9. Construction. This Note shall be construed and enforced in
accordance with the domestic, internal law, but not the law of conflict of laws,
of the State of New York.

         10. Severability. Any provision contained in this Note which is
prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction,
be ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction.

         IN WITNESS WHEREOF, Maker, intending to be legally bound hereby, has
caused this Note to be duly executed by its Chief Executive Officer the day and
year first above written.


                                     VECTOR INTERSECT SECURITY ACQUISITION CORP.



                                     By:  /s/ Yaron Eitan
                                          --------------------------------------
                                          Name: Yaron Eitan
                                          Title: Chief Executive Officer