EMERSON ELECTRIC CO — Director's Dealing 2006

Mar 9, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2006-03-07

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
2006-03-07	Common Stock	S	29000	$22.0919	Disposed	7973041	Indirect
2006-03-08	Common Stock	S	32752	$22.1059	Disposed	7940289	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 29,000 shares on March 7, 2006. In the discretion of the broker, the sales were effected in multiple transactions,
at varying prices, on March 7, 2006, as follows and as described in Footnote 2 below: 500 shares at $21.90; 1,700 at $21.91;
200 at $21.92; 400 at $21.93; 800 at $21.94; 1,600 at $21.95; 900 at $21.96; 600 at $21.97; 600 at $21.98; 700 at $21.99;
2,000 at $22.00; 1,000 at $22.01; 900 at $22.02; 400 at $22.03; 200 at $22.04; 100 at $22.05; 100 at $22.07; 100 at $22.08;
300 at $22.11; 400 at $22.13; 500 at $22.14; 4,200 at $22.15; and 1,400 at $22.16.

F2: This footnote sets forth additional detail with respect to the transactions described in Footnote 1, as follows: 1,000 shares
at $22.17; 1,200 at $22.18; 900 at $22.19; 700 at $22.20; 1,300 at $22.21; 1,110 at $22.22; 1,100 at $22.23; 790 at $22.24;
100 at $22.25; 100 at $22.26; 200 at $22.28; 300 at $22.29; 300 at $22.30; 137 at $22.31; and 163 at $22.32. The weighted
average sales price for these transactions was $22.0919 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 32,752 shares on March 8, 2006. In the discretion of the broker, the sales weres effected in multiple
transactions, at varying prices, on March 8, 2006, as follows and as described in Footnote 5 below : 100 shares at $21.82;
100 at $21.86; 400 at $21.90; 200 at $21.91; 300 at $21.92; 700 at $21.93; 100 at $21.94; 700 at $21.95; 1,300 at $21.96;
136 at $21.97; 64 at $21.98; 100 at $21.99; 100 at $22.00; 800 at $22.01; 1,200 at $22.02; 700 at $22.03; 1,002 at $22.04;
1,000 at $22.05; 600 at $22.06; 500 at $22.07; 1,400 at $22.08; 668 at $22.09; and 800 at $22.10.

F5: This footnote sets forth additional detail with respect to the transactions described in Footnote 4, as follows: 1,953 shares
at $22.11; 2,519 at $22.12; 2,610 at $22.13; 1,157 at $22.14; 743 at $22.15; 1,200 at $22.16; 1,300 at $22.17; 1,700 at
$22.18; 1,500 at $22.19; 1,600 at $22.20; 960 at $22.21; 1,100 at $22.22; 200 at $22.23; 299 at $22.24; 201 at $22.25; 40 at
$22.26; and 700 at $22.27. The weighted average sales price for these transactions was $22.1059 per share.

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