The Blam RA251D is an ultra-compact Class D monoblock amplifier designed to add a subwoofer to factory systems while remaining compatible with OEM head units. It features high-level inputs with auto-turn on for seamless connection to original car radios.

The amplifier delivers 150 Watts RMS into 4 Ohm and 250 Watts RMS into 2 Ohm, with an adjustable low-pass crossover from 35 Hz to 500 Hz (12 dB/octave), frequency response 15 Hz to 500 Hz, and bass boost of +12 dB at 45 Hz. It includes RCA low-level inputs (0.3 V to 15 V), an external wired remote control, built-in protections for short circuit, low impedance, polarity reversal and overheating, and measures 158 mm x 36 mm x 91.4 mm (6.2 in x 1.4 in x 3.6 in). Supplied accessories include mounting screws, user manual and external remote control.