Sealed ( acoustic suspension) powered subwoofer.

TR3 Subwoofer

• Design: Sealed Steel Enclosure
• Driver: 10″ Aluminum
• MFR: 22 Hz – 180 Hz
• Power Amplifier: 300 Watts RMS, Class AB
• Phase: Two-position Toggle Switch – 00 or 1800
• Low Pass : 50 to 180 Hz, Continuously Variable
• High Pass: 80 Hz Fixed, Only on High-level Output
• Bass EQ: 0, +3 dB, +6 dB
• Power On/Off: Three-way Toggle
• Connections: Line-level RCA, Speaker-level Binding Posts
• Dimensions: 12″ H x 10.75″ W x 13.5″ D
• Weight: 36 Pounds