EMERSON ELECTRIC CO — Director's Dealing 2006

Sep 21, 2006

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2006-09-19

Reporting Person: EMERSON ELECTRIC CO (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2006-09-19	Common Stock	S	25000	$20.3331	Disposed	3646249	Indirect
2006-09-20	Common Stock	S	25000	$20.8107	Disposed	3621249	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 19, 2006, as follows and as described in
Footnote 2 below: 200 shares at $20.08; 800 at $20.12; 600 at $20.13; 100 at $20.14; 600 at $20.15; 500 at $20.16; 400 at
$20.17; 1,100 at $20.18; 500 at $20.19; 700 at $20.20; 900 at $20.21; 400 at $20.22; 200 at $20.23; 200 at $20.25; 200 at
$20.26; 643 at $20.27; 1,100 at $20.28; 400 at $20.29; 107 at $20.30; 400 at $20.31; 500 at $20.32; 1,000 at $20.33; 900 at
$20.34; and 334 at $20.35.

F2: This footnote sets forth additional detail with respect to the transactions described in Footnote 1, as follows: 525 shares
at $20.36; 1,143 at $20.37; 237 at $20.38; 500 at $20.39; 763 at $20.40; 1,400 at $20.41; 781 at $20.42; 800 at $20.43; 619
at $20.44; 1,800 at $20.45; 700 at $20.46; 500 at $20.47; 148 at $20.48; 500 at $20.50; 600 at $20.51; 200 at $20.52; 300 at
$20.53; 500 at $20.54; and 200 at $20.57. The weighted average sales price for these transactions was $20.3331 per share.

F3: The sales were effected in multiple transactions, at varying prices, on September 20, 2006, as follows: 200 shares at $20.51;
200 at $20.52; 100 at $20.54; 200 at $20.56; 100 at $20.59; 100 at $20.60; 200 at $20.64; 400 at $20.65; 500 at $20.67;
1,200 at $20.68; 1,000 at $20.69; 1,323 at $20.70; 1,003 at $20.71; 600 at $20.72; 200 at $20.74; 200 at $20.75; 100 at
$20.76; 600 at $20.77; 100 at $20.79; 100 at $20.81; 1,200 at $20.82; 1,000 at $20.83; 1,000 at $20.84; 2,187 at $20.85;
1,900 at $20.86; 1,301 at $20.87; 1,914 at $20.88; 1,200 at $20.89; 2,031 at $20.90; 1,096 at $20.91; 500 at $20.92; 500 at
$20.93; and 745 at $20.94. The weighted average sales price for these transactions was $20.8107 per share.