**Exhibit 21**

**AMERICAN POWER CONVERSION CORPORATIONSubsidiaries as of December 31, 2005**

| **Subsidiary**                                                                    | ** ** | ** **      | ** ** | **Place of  Incorporation** |
|-----------------------------------------------------------------------------------|------------|-----------------|------------|-----------------------------|
|                                                                              |       |            |
| APC America, Inc.                                                            |       | Delaware        |
| APC Sales &  Service Corp.                                               |       | Delaware        |
| American Power  Conversion Holdings Inc.                                          |       | Delaware        |
| Netbotz, Inc.                                                                |       | Delaware        |
| Systems Enhancement  Corporation                                                  |       | Missouri        |
| A.B.L. Electronics  Corporation                                                   |       | Delaware        |
| APC DC Network Solutions  Inc.                                                    |       | Ohio            |
| American Power  Conversion Europe S.A.R.L.                                        |       | France          |
| American Power  Conversion Corporation (A.P.C.) B.V.                              |       | The Netherlands |
| APC Distribution Limited                                                          |       | Ireland         |
| APC (EMEA) Limited                                                                |       | Ireland         |
| APC Holdings B.V.                                                                 |       | The Netherlands |
| APC Deutschland GmbH                                                              |       | Germany         |
| American Power  Conversion UK Ltd.                                                |       | United Kingdom  |
| American Power  Conversion Sweden AB                                              |       | Sweden          |
| APC Benelux B.V.                                                                  |       | The Netherlands |
| APC Australia Pty  Limited                                                        |       | Australia       |
| American Power  Conversion Portugal, Ltda.                                        |       | Portugal        |
| American Power  Conversion Spain S.L.                                             |       | Spain           |
| American Power  Conversion Italia S.R.L.                                          |       | Italy           |
| American Power  Conversion France SARL                                            |       | France          |
| APC Korea Corporation                                                             |       | Korea           |
| American Power  Conversion Hong Kong Limited                                      |       | Hong Kong       |
| American Power  Conversion Poland Sp. z.o.o.                                      |       | Poland          |
| American Power  Conversion (Phils.), Inc.                                    |       | Philippines     |
| American Power  Conversion Land Holdings Inc. (40%; 60% Filipino nationals***)*** |       | Philippines     |
| APC (Suzhou)  Uninterrupted Power Supply Co., Ltd.                                |       | China           |
| American Power  Conversion Singapore Pte Ltd.                                     |       | Singapore       |
| APC International Trade  (Shanghai) Co. Ltd.                                      |       | China           |
| APC Europe B.V.                                                                   |       | Netherlands     |
| APC (Xiamen) Power Infrastructure  Co. Ltd.                                       |       | China           |
| American Power  Conversion Denmark ApS                                            |       | Denmark         |
| Gutor Electronic GmbH                                                             |       | Switzerland     |
| American Power  Conversion Dublin Limited                                         |       | Ireland         |
| Silcon (Qingdao) Power  Electronics Co. Ltd.                                      |       | China           |
| Gutor Electronic Asia  Pacific Sdn Bhd                                            |       | Malaysia        |
| American Power  Conversion Mexico, S.A. de C.V.                                   |       | Mexico          |
| American Power  Conversion Uruguay S.A.                                           |       | Uruguay         |
| APC Japan, Inc.                                                              |       | Japan           |
| American Power  Conversion (India) Private Limited                                |       | India           |
| American Power  Conversion Brasil Ltda.                                           |       | Brazil          |
| American Power  Conversion Holdings (UK) Limited                                  |       | United Kingdom  |
| APC DC Network Solutions UK Limited                                               |       | United Kingdom  |

 

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