EMERSON ELECTRIC CO — Director's Dealing 2006

Mar 7, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

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

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
2006-03-03	Common Stock	S	24432	$22.5996	Disposed	8035041	Indirect
2006-03-06	Common Stock	S	33000	$22.2673	Disposed	8002041	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 24,432 shares on March 3, 2006. In the discretion of the broker, the sales were effected in multiple transactions,
at varying prices, on March 3, 2006, as follows and as described in Footnote 2 below: 600 shares at $22.31; 1,300 at $22.32;
908 at $22.33; 400 at $22.34; 792 at $22.35; 200 at $22.37; 200 at $22.38; 700 at $22.39; 500 at $22.40; 500 at $22.41; 400
at $22.42; 100 at $22.43; 100 at $22.44; 100 at $22.45; 100 at $22.47; 200 at $22.48; 100 at $22.49; 100 at $22.50; 200 at
$22.51; 100 at $22.52; 900 at $22.54; 200 at $22.55; and 224 at $22.56.

F2: This footnote sets forth additional detail with respect to the transactions described in Footnote 1, as follows: 100 shares
at $22.57; 100 at $22.61; 200 at $22.63; 600 at $22.64; 500 at $22.65; 700 at $22.66; 500 at $22.67; 1,400 at $22.68; 400 at
$22.69; 300 at $22.70; 500 at $22.71; 200 at $22.72; 4,300 at $22.73; 1,900 at $22.74; 3,708 at $22.75; and 100 at $22.76.
The weighted average sales price for these transactions was $22.5996 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 33,000 shares on March 6, 2006. In the discretion of the broker, the sales weres effected in multiple
transactions, at varying prices, on March 6, 2006, as follows and as described in Footnote 5 below : 200 shares at $22.00;
200 at $22.01; 400 at $22.04; 100 at $22.06; 400 at $22.07; 100 at $22.08; 300 at $22.09; 1,092 at $22.10; 843 at $22.11;
765 at $22.12; 1,100 at $22.13; 400 at $22.14; 100 at $22.15; 400 at $22.17; 700 at $22.18; 200 at $22.19; 4,500 at $22.20;
500 at $22.21; 200 at $22.24; 2,187 at $22.25; 400 at $22.26; 700 at $22.27; 213 at $22.28; 2,100 at $22.30; 3,570 at
$22.31; 2,100 at $22.32; 530 at $22.33; and 200 at $22.34.

F5: This footnote sets forth additional detail with respect to the transactions described in Footnote 4, as follows: 1,300 shares
at $22.35; 900 at $22.36; 600 at $22.37; 300 at $22.38; 1,700 at $22.40; 1,100 at $22.41; 1,000 at $22.42; 500 at $22.43;
600 at $22.44; 100 at $22.48; and 400 at $22.49. The weighted average sales price for these transactions was $22.2673 per
share.

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