Specifications:

Plug and play: Frequencies are already carefully tuned and ready to use, with no tuning required, which means sound engineers no longer have to spend valuable pre-show and studio time tuning monitors.
His and hers: The Ultimate Ears Vocal Reference Monitors are offered in male and female versions, since vocal frequencies vary between the two.
Passive noise cancellation: The custom monitor acts as an earplug and reduces overall stage volume by 26 decibels. By lowering the sound pressure levels to a safer zone, vocalists can hear their own voice more clearly.
Customized frequency delivery: Three balanced armatures are utilized in each ear; each of the three armatures focuses all its energy on a narrow frequency band and together they cleanly produce the spectrum of speech, which falls into the frequency range of 90Hz – 8kHz
Compatible with devices that support a standard 1/8 inch (3.5mm) headphone jack
Frequency response: 90Hz – 8kHz
Noise isolation: -26 dB
Input Connection: 3.5mm (1/8 inch)
Input sensitivity: 98 dB @ 1 kHz
1-year warranty on the performance of the monitors, cable, housing and internal speakers
30-day warranty on fit for all custom in-ear monitors

Ultimate Ears UE Vocal Reference Monitors