in ear, behringer

Behringer Powerplay PM1 1-Channel Personal In-ear Monitor Beltpack In-ear Monitor Beltpack with Metal Housing, Belt Clip, Volume Control, 3.5mm Headphone Output, and XLR Input
  Behringer Powerplay PM1 1-Channel Personal In-ear Monitor Beltpack (PM-1 / PM 1)

The Behringer Powerplay PM1 restores freedom of movement to the in-ear user.

In-ear Monitor Powered Amplifer with XLR/TRS Combo Input and 3.5mm TRS Headphone Output
  Behringer P2 Ultra-Compact Personal In-Ear Monitor Amplifier (P-2 / P 2)

The Powerplay P2 is the powered successor to Behringer's completely passive PM1 personal in-ear monitor amp.