Table 1. Skullcap Characteristics.

Table 1 shows the measured dimensions and acoustic properties of the three skullcaps.

Skull #	Major Dimensions (mm)			Thickness (mm)			Acoustic Properties
	Long Axis	Short Axis	Depth	Min	Max	Mean	250 kHz Attenuation (dB/cm)	500 kHz Attenuation (dB/cm)	Sound Speed (m/s)
1	161	139	58	2.1	8.5	5.1 ± 1.3	14.4 ± 5.2	20.4 ± 6.6	2063 ± 402
2	173	145	63	3.7	10.4	7.0 ± 1.5	11.4 ± 4.3	11.7 ± 3.4	1991 ± 210
3	183	143	64	2.6	11.1	6.5 ± 1.3	14.6 ± 7.7	14.5 ± 4.5	2340 ± 354