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HEARING PROTECTION

HEARING PROTECTION

EP4 Sonic Defenders

® 

Plus

Two Levels of Protection Against Two Types of Noise

Filtered EP4 Sonic Defenders 

Plus provide two levels of protection—

with their attached filter caps in or out—against two types of noise: 

continuous noise (example: loud roar of an engine) and impulse noise 

(example: gunshot). With the filter caps out of the noise-reducing 

filters, loud potentially dangerous sounds (above 85dB) are lowered 

while safe-level ambient sounds and conversations are allowed to 

pass through and be heard. With the filter caps inserted, additional 

hearing protection is afforded and ambient sounds and conversations 

are blocked. 

FOR PROTECTION WITH THE ABILITY TO HEAR AMBIENT SOUNDS,

 

leave filter caps out, or pry out with your fingernail if already inserted.

 

FOR MAXIMUM 

PROTECTION OR SITUATIONS WHERE YOU DON’T WANT TO HEAR AMBIENT 
SOUNDS,

 

insert filter caps into filter holes and push in until snug.

NOISE ATTENUATION DATA

WARNING:

 

Improper fit of this device will reduce its effectiveness in attenuating noise. 

Follow instructions for proper fit. Failure to follow instructions could result in hearing loss 
and/or injury. EP4 Sonic Defenders 

Plus fit most people; however, no hearing protection fits 

everyone. If proper fit cannot be achieved following instructions, discontinue use. Do not 
use in environments with extreme air/water pressure or where abrupt pressure changes 
occur. EP4s should not be worn underwater in depths exceeding one meter. 

EP4 Sonic Defenders Plus - 

FILTER CAPS OUT

NOISE REDUCTION RATING (NRR)

EP4 Sonic Defenders Plus - 

FILTER CAPS IN

(when used as directed)

(when used as directed)

12

NRR

Test Frequencies (Hz)
Mean Attenuation (dB)
Standard Deviation (dB)

125

9.7
3.7

250

10.5

3.4

500

15.6

2.4

1000

20.4

3.0

2000

29.0

3.0

3150

32.0

5.8

4000

28.2

5.6

8000

36.9

5.7

6300

30.2

5.5

24

NRR

Test Frequencies (Hz)
Mean Attenuation (dB)
Standard Deviation (dB)

125

31.7

5.4

250

29.3

4.6

500

32.9

4.3

1000

30.5

3.2

2000

35.6

4.1

3150

37.2

4.2

4000

35.0

3.6

8000

37.7

5.5

6300

34.4

4.1

WITH FILTER CAPS OUT

WITH FILTER CAPS IN

132 dB Overall Average PIL
150 dB Overall Average PIL
168 dB Overall Average PIL

23.9
28.8
30.0

Average Peak Impulse Level

dB Reduction

132 dB Overall Average PIL
150 dB Overall Average PIL
168 dB Overall Average PIL

39.8
40.7
40.5

Average Peak Impulse Level

dB Reduction

NOISE REDUC

TION (

dB)

EP4 Impulse Noise Reduction—

Filter Caps Out

ANSI S12.42-2010

45
40
35
30
25
20

15
10

5
0

 

132 

            150

 

                       

168

IMPULSE NOISE LEVEL (dB)

132 dB Overall Average PIL
150 dB Overall Average PIL
168 dB Overall Average PIL

23.9
28.8
30.0

Average Peak Impulse Level

dB Reduction

132 dB Overall Average PIL
150 dB Overall Average PIL
168 dB Overall Average PIL

39.8
40.7
40.5

Average Peak Impulse Level

dB Reduction

ANSI S12.42-2010

NOISE REDUC

TION (

dB)

EP4 Impulse Noise Reduction—

Filter Caps In

45
40
35
30
25
20

15
10

5
0

 

132 

            150

 

                       

168

IMPULSE NOISE LEVEL (dB)

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