EMERSON ELECTRIC CO — Director's Dealing 2006

Sep 19, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2006-09-15

Reporting Person: EMERSON ELECTRIC CO (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2006-09-15	Common Stock	S	125000	$20.5084	Disposed	3696249	Indirect
2006-09-18	Common Stock	S	25000	$20.7086	Disposed	3671249	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	1065182	Direct

Footnotes

F1: The sales were effected in multiple transactions, at varying prices, on September 15, 2006, as follows: 200 shares at $20.41;
600 at $20.42; 200 at $20.43; 600 at $20.44; 806 at $20.45; 700 at $20.46; 2,280 at $20.47; 4,020 at $20.48; 17,100 at
$20.49; 38,248 at $20.50; 24,514 at $20.51; 10,472 at $20.52; 11,078 at $20.53; 5,354 at $20.54; 2,428 at $20.55; 2,300 at
$20.56; 3,200 at $20.57; 700 at $20.58; and 200 at $20.60. The weighted average sales price for these transactions was
$20.5084 per share.

F2: The sales were effected in multiple transactions, at varying prices, on September 18, 2006, as follows and as described in
Footnote 3 below: 200 shares at $20.47; 100 at $20.49; 100 at $20.50; 800 at $20.52; 500 at $20.53; 200 at $20.54; 100 at
$20.55; 400 at $20.56; 900 at $20.57; 1,100 at $20.58; 700 at $20.59; 1,100 at $20.60; 1,007 at $20.61; 866 at $20.62; 200
at $20.63; 1,010 at $20.64; 900 at $20.65; 1,002 at $20.66; 300 at $20.67; 200 at $20.68; 600 at $20.69; 200 at $20.70; 200
at $20.71; 1,800 at $20.72; 1,400 at $20.73; 800 at $20.74; and 589 at $20.75.

F3: This footnote sets forth additional detail with respect to the transactions described in Footnote 2, as follows: 200 shares
at $20.76; 500 at $20.77; 100 at $20.78; 341 at $20.79; 200 at $20.80; 600 at $20.81; 500 at $20.82; 800 at $20.83; 500 at
$20.84; 400 at $20.85; 200 at $20.86; 400 at $20.88; 500 at $20.89; 300 at $20.90; 300 at $20.91; 100 at $20.92; 500 at
$20.93; 400 at $20.94; 100 at $20.95; 285 at $20.96; 300 at $20.99; and 200 at $21.00. The weighted average sales price for
these transactions was $20.7086 per share.