UNITEDTable STATES SECURITIESof AND EXCHANGE COMMISSION Contents

~~WASHINGTON~~UNITED ~~D.C.~~STATES SECURITIES ~~20549~~AND EXCHANGE COMMISSION

~~FORM~~WASHINGTON ~~8-K~~D.C. 20549

~~CURRENT~~FORM ~~REPORT~~8-K ~~PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934~~

~~Date~~CURRENT ofREPORT PURSUANT ~~Report~~TO SECTION 13 OR 15(~~Date~~d) ofOF ~~earliest~~THE ~~event~~SECURITIES ~~reported): May 24,~~EXCHANGE ~~2011~~ACT OF 1934

~~RAE~~Date ~~Systems~~of ~~Inc.~~Report (Date of earliest event reported): May 26, 2011

~~(Exact~~RAE ~~name~~Systems ~~of registrant as specified in its charter)~~Inc.

Delaware		001-31783		77-0280662
(State or other jurisdiction of incorporation)		(Commission File No.)		(I.R.S. Employer Identification No.)

(Exact name of registrant as specified in its charter)

~~3775~~Delaware ~~North~~(State ~~First~~or ~~Street San~~other ~~Jose,~~jurisdiction ~~California~~of ~~95134 408~~incorporation) 001-~~952-8200~~ 31783 (~~Address~~Commission ~~and~~File ~~telephone~~No.) ~~number~~77-0280662 of(I.R.S. ~~registrant’s~~Employer ~~principal~~Identification ~~executive offices~~No.)

~~Check~~ 3775 ~~the~~North ~~appropriate~~First ~~box~~Street San ~~below~~Jose, ifCalifornia ~~the Form 8~~95134 408-K952-8200 (Address ~~filing~~and istelephone ~~intended~~number ~~to simultaneously satisfy the filing obligation~~ of ~~the~~ registrant’s ~~under~~principal ~~any~~executive ~~of the following provisions:~~ offices)

oCheck ~~Written~~the ~~communications~~appropriate ~~pursuant~~box below if the Form 8-K filing is intended to ~~Rule 425~~simultaneously ~~under~~satisfy the filing ~~Securities~~obligation ~~Act~~of ~~(17~~the ~~CFR~~registrant ~~230.425)~~ under any of the following provisions:

o ~~Soliciting~~Written ~~material~~communications pursuant to Rule ~~14a-12~~425 under the ~~Exchange~~Securities Act (17 CFR ~~240~~230.~~14a-12~~425)

o ~~Pre-commencement~~Soliciting ~~communications~~material pursuant to Rule ~~14d~~14a-~~2(b)~~12 under the Exchange Act (17 CFR 240.~~14d~~14a-~~2(b~~12))

o Pre-commencement communications pursuant to Rule ~~13e~~14d-42(cb) under the Exchange Act (17 CFR 240.~~13e~~14d-42(cb))

~~Item~~o Pre-commencement communications pursuant to Rule ~~1.01~~13e-4(c) ~~Entry~~under ~~into~~the aExchange ~~Material~~Act ~~Definitive~~(17 ~~Agreement~~CFR 240. 13e-4(c))

~~Amendment~~TABLE ~~No. 4~~OF ~~to Agreement and Plan of Merger~~CONTENTS

OnItem ~~May 24, 2011, RAE Systems Inc~~1.01 ~~(the~~Entry ~~“Company”) entered~~ into an amendment (the “Amendment”) to the Agreement and Plan of Merger dated as of January 18, 2011, as amended on April 3, 2011, May 17, 2011 and May 20, 2011 and as it may be further amended from time to time (the “Merger Agreement”) with Ray Holding Corporation (“Purchaser”) and Ray Merger Sub Corporation (“Merger Sub”), a ~~wholly~~Material ~~owned~~Definitive ~~subsidiary of Purchaser~~Agreement. ~~Purchaser~~Item and Merger Sub are each affiliates of Vector Capital IV, L.P and Vector Capital III, L.P. (collectively, “Vector”). Pursuant to the Amendment, Purchaser has increased the price per share to be paid to the Company’s unaffiliated stockholders from $2.0501 ~~per~~Completion ~~share to $2.25 per share, without interest. In addition, the termination fee payable upon termination~~ of ~~the~~Acquisition ~~Merger Agreement under specified circumstances was increased from $4.27 million to $5.75 million (reduced by any expense reimbursement paid~~ or ~~payable under~~Disposition the Merger Agreement). Pursuant to an amendment to the Guarantee Agreement (the “Guarantee Amendment”) among Vector Capital IV, L.P., Vector Capital III, L.P. and the Company, the cap on Vector’s obligation to guarantee the obligations of ~~Purchaser and Merger Sub to pay the cash merger consideration was increased to $107,651,000 minus an amount equal to the product of $2~~Assets.~~25 multiplied~~ byItem ~~the number of shares of the Company’s common stock to be transferred by Mr~~9. ~~Robert Chen~~01 toFinancial ~~the~~Statements Purchaser for which cash consideration will not be paid. The Amendment was unanimously approved by the Special Committee of the Board of Directors of the Company. The Purchaser proposed this amendment on May 24, 2011 following a definitive proposal submitted on May 24, 2011 by Battery Ventures and ~~SFW~~Exhibits ~~Capital~~SIGNATURE toEXHIBIT ~~acquire~~INDEX ~~the~~EXHIBIT ~~Company for $2~~10.~~20 per share. The transaction is subject to customary closing conditions, including the approval of RAE’s stockholders. There is no financing condition to the transaction.~~ 24

TheTable foregoing descriptions of the Amendment and Guarantee Amendment are only summaries, do not purport to be complete and are qualified in their entirety by reference to the Amendment and the Guarantee Amendment, copies of which are furnished as Exhibits 2.1 and 10.1, respectively, to this report. Contents

~~Additional~~Item ~~Information~~1.01 ~~About~~Entry ~~the~~into ~~Amendment~~a ~~and~~Material ~~Where~~Definitive ~~You Can Find It~~ Agreement.

In On ~~connection~~May 26, ~~with entry into of the Amendment~~2011, the Company’s ~~will~~majority-owned ~~file~~subsidiary, aRAE-KLH ~~supplement~~(Beijing) toTechnologies ~~the~~Co., ~~proxy~~Ltd. ~~statement filed with the Securities and Exchange Commission~~ (~~the~~ “~~Commission~~RAE KLH”) ~~on March 9~~, ~~2011,~~ asentered ~~supplemented~~into onan ~~March 16,~~agreement ~~2011,~~to ~~March 28,~~sell ~~2011~~a ~~and~~building ~~May 12,~~in ~~2011~~Beijing, ~~for~~China ~~the Company’s special stockholder meeting and stockholders are strongly advised~~ to ~~read~~Beijing ~~the proxy statement and all~~Beike ~~subsequent~~Yongfeng ~~supplements~~Technologies toDevelopment ~~the~~Co., ~~proxy~~Ltd. ~~statement~~The ~~when~~purchase ~~they~~price ~~become~~is ~~available~~approximately ~~because they contain~~$8.47 million, ~~important~~payable ~~information~~$4.62 million ~~about~~on ~~the~~signing, ~~merger~~$3.08 million ~~Investors~~on ~~and~~February 28, ~~stockholders~~2012, ~~may~~and ~~obtain~~$770,000 ~~free~~on ~~copies of the~~February 28, ~~proxy~~2013. ~~statement~~RAE ~~(including~~KLH ~~all~~has ~~supplements~~agreed to indemnify the ~~proxy~~purchaser ~~statement)~~against ~~and~~liabilities ~~other~~associated ~~documents~~with ~~filed by~~ the ~~Company~~property atthat ~~the~~arose ~~Commission’s~~prior ~~web site at http://www.sec.gov. The proxy statement (including all supplements~~ to the ~~proxy~~purchase ~~statement)~~ and other relevant documents may also be obtained for free by directing a request to the Company’s Investor Relations Agency Lippert/Heilshorn & Associates at (415) 433-3777 or RAE Systems IR c/o Lippert/Heilshorn & Associates, 44 Montgomery Street, Suite 3520, San Francisco, California 94104sale.

Item 9 2.01 ~~Financial~~Completion ~~Statements~~of ~~and~~Acquisition ~~Exhibits~~or Disposition of Assets.

~~(d)~~ See disclosure under Item ~~Exhibits~~1.01 above.

Exhibit		Description
2.1		Amendment No. 4 to Agreement and Plan of Merger, dated as of May 24, 2011, by and among RAE Systems Inc., Ray Holding Corporation and Ray Merger Sub Corporation.
10.1		Amendment No. 4 to Guarantee, dated as of May 24, 2011, by and among Capital IV, L.P., Vector Capital III, L.P. and the Company.


Item 9.01		Financial Statements and Exhibits.

SIGNATURE


(c) Exhibit No.		Description
10.24		Amendment Agreement between Beijing Beike Yongfeng Technologies Development Co., Ltd. and RAE-KLH (Beijing) Technologies Co., Ltd. dated May 26, 2011

PursuantTable to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Contents

~~Date: May 25, 2011~~SIGNATURE

~~RAE~~Pursuant ~~SYSTEMS~~to ~~INC.~~the ~~By:~~requirements ~~/s/~~of ~~Randall~~the ~~Gausman~~Securities ~~Name:~~Exchange ~~Randall~~Act ~~Gausman~~of ~~Title:~~1934, ~~Vice~~as ~~President~~amended, ~~and~~the ~~Chief~~Registrant ~~Financial~~has duly ~~Officer~~caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

~~EXHIBIT~~Date: ~~INDEX~~ June 1, 2011

Exhibit		Description
2.1		Amendment No. 4 to Agreement and Plan of Merger, dated as of May 24, 2011, by and among RAE Systems Inc., Ray Holding Corporation and Ray Merger Sub Corporation.
10.1		Amendment No. 4 to Guarantee, dated as of May 24, 2011, by and among Capital IV, L.P., Vector Capital III, L.P. and the Company.


RAE SYSTEMS INC.
By:	/s/ Randall Gausman
	Name:	Randall Gausman
	Title:	Vice President and Chief Financial Officer

EXHIBIT INDEX


Exhibit		Description
10.24		Amendment Agreement between Beijing Beike Yongfeng Technologies Development Co., Ltd. and RAE-KLH (Beijing) Technologies Co., Ltd. dated May 26, 2011

UNITEDTable STATES SECURITIESof AND EXCHANGE COMMISSION Contents

PursuantTable to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Contents

Table of Contents

Filing Compare · RAE SYSTEMS INC