EMERSON ELECTRIC CO — Director's Dealing 2006

Mar 3, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2006-03-01

Reporting Person: EMERSON ELECTRIC CO (10% Owner)
Reporting Person: ASTEC AMERICA INC (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2006-03-01	Common Stock	S	66000	$22.7363	Disposed	8122565	Indirect
2006-03-02	Common Stock	S	63092	$22.5606	Disposed	8059473	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	1065182	Direct

Footnotes

F1: The Reporting Person gave a sell order to the broker to sell shares of MKS Instruments, Inc. common stock which resulted in
sales of 66,000 shares on March 1, 2006. In the discretion of the broker, the sales were effected in multiple transactions,
at varying prices, on March 1, 2006, as follows and as described in Footnote 2 below: 5,100 shares at $22.40; 1,800 at
$22.41; 700 at $22.42; 600 at $22.44; 1,847 at $22.45; 153 at $22.46; 300 at $22.47; 200 at $22.48; 300 at $22.49; 400 at
$22.50; 700 at $22.51; 300 at $22.52; 200 at $22.53; 100 at $22.54; 300 at $22.55; 500 at $22.56; 700 at $22.58; 200 at
$22.59; 700 at $22.63; 346 at $22.64; 1,300 at $22.65; and 1,100 at $22.66.

F2: This footnote sets forth additional detail with respect to the transactions described in Footnote 1, as follows: 1,000 shares
at $22.67; 800 at $22.68; 1,600 at $22.69; 1,100 at $22.70; 500 at $22.71; 2,000 at $22.72; 2,900 at $22.73; 1,900 at
$22.74; 1,400 at $22.75; 2,200 at $22.76; 1,355 at $22.77; 892 at $22.78; 3,303 at $22.79; 800 at $22.80; 2,500 at $22.81;
800 at $22.82; 800 at $22.8287; 700 at $22.83; 1,800 at $22.84; 3,100 at $22.85; 900 at $22.86; 400 at $22.87; 600 at
$22.88; 1,700 at $22.89; 400 at $22.90; 1,000 at $22.91; 800 at $22.92; 700 at $22.93; 2,800 at $22.94; 200 at $22.945;
1,200 at $22.95; 1,204 at $22.96; 800 at $22.97; 600 at $22.98; 400 at $22.985; 1,000 at $22.99; 200 at $22.9985; 600 at
$23.00; 300 at $23.01; 400 at $23.02; 300 at $23.03; and 200 at $23.04. The weighted average sales price for these
transactions was $22.7363 per share.

F3: The reported securities are owned directly by Astec America Inc. The Reporting Person is the ultimate parent company of
Astec America Inc.

F4: The Reporting Person gave a sell order to the broker to sell shares of MKS Instruments, Inc. common stock which resulted in
sales of 63,092 shares on March 2, 2006. In the discretion of the broker, the sales weres effected in multiple
transactions, at varying prices, on March 2, 2006, as follows and as described in Footnote 5 below : 600 shares at $22.40;
1,100 at $22.41; 300 at $22.42; 1,500 at $22.44; 140 at $22.48; 200 at $22.49; 11,909 at $22.50; 6,600 at $22.51; 700 at
$22.52; 2,000 at $22.53; 14,200 at $22.54; 300 at $22.55; 6,392 at $22.56; 3,460 at $22.57; 300 at $22.58; 1,000 at $22.59;
500 at $22.60; 900 at $22.62; 1,000 at $22.63; 1,300 at $22.64; 200 at $22.65; 600 at $22.66; 215 at $22.67; 285 at $22.68;
300 at $22.69; 100 at $22.70; 100 at $22.71; and 300 at $22.72.

F5: This footnote sets forth additional detail with respect to the transactions described in Footnote 4, as follows: 1,400 shares
at $22.73; 618 at $22.74; 700 at $22.75; 600 at $22.76; 600 at $22.77; 400 at $22.78; 300 at $22.79; 700 at $22.80; 500 at
$22.81; 200 at $22.82; 300 at $22.83; 173 at $22.84; and 100 at $22.90. The weighted average sales price for these
transactions was $22.5606 per share.

F6: The reported securities are owned directly by Emerson Electric Co.