QSC ISA450 is a ISA Install Professional Power Amplifier  System. And it  designed to meet the needs of sound system designers and contractors worldwide. The ISA Series a rugged, cost-effective power solution for any permanently installed sound system. Frequency Response: 20 Hz-20 kHz, +0/-1 dB Stereo Mode: 260 W for 8Ω, 425 W for 4Ω, 700 W for 2Ω Bridge Mono Mode: 900 W for 8Ω, 1400 W for 4Ω Dimensions (H x W x D): 5.25" (13.3 cm) 3 rack spaces x 19" (48.3 cm) rack mounting x 15.9" (40 cm) deep from front mounting rails

QSC CX902 is a 2 channel Low-Z Power Amplifier. Exclusive Power Light switch-mode power supply technology for high performance and compact size. QSC CX902 in the Active inrush limiting eliminates AC inrush current, removing the need for expensive power sequencers. XLR and detachable Euro style input connectors. Frequency Response: 20 Hz–20 kHz, ±0.2 dB Stereo Mode: 550 W for 8 Ω, 900 W for 4 Ω, 1500 W for 2Ω, 400 W for 70V / 20 Hz – 20 kHz, 440 W for 70V / 1 kHz, 600 W for 70V / 1 kHz Bridged Mono Mode: 1100 W for 16Ω, 2000 W for 8Ω, 3000 W for 4Ω, 800 W for 140V / 20 Hz – 20 kHz, 880 W for 140V /  1 kHz / 0.05% THD,1200 W for 140V / 1 kHz / 1% THD Dimensions (H x W x D): 3.5" x 19" x 14"(89 mm x 483 mm x 356 mm)

QSC CX404 is a 4 Channel Professional Power Amplifier. It gives four channels in only two rack spaces, without compromising on power. CX404 is equip with exclusive QSC Power Light switching power supply technology to virtually eliminate noise and hum. Frequency Response 20 Hz - 20 kHz, ± 0.2 dB | 8 Hz - 50 kHz, + 0/-3 dB Stereo Mode: 250 W for 8Ω, 400 W for 4Ω (0.1% THD, 1 kHz) Bridge-Mono Mode: 500 W for 16Ω, 800 W for 8Ω (0.1% THD, 1 kHz) Dimensions (H x W x D): 3.5" (8.9 cm) 2 RU x 19" (48.3 cm) rack mounting x 14" (35.6 cm) from front mounting rails