DH-132 tanker's helmet and triple flange earplug		
"USAARL Report No. 93-10, Jan 1993"		
Freq(Khz) Mean_Gain(dB) StDev_Gain(dB) Note: -10dB Gain = 10dB Attenuation		
0.0625	-25.3	1.2
0.125	-32	5.3
0.25	-37.1	6
0.5	-40.2	5.4
1	-34.9	5.2
2	-34	4.8
4	-43.1	4.5
8	-47.4	6
