PS652 : 5" 3 Way Speaker System, Max Power:100 Watts x 2. Injection Moulded Carbon Fibre Cone, Frequency Response:40Hz-30KHz, Mounting Depth: 50mm. PS650 : 4" 3 Way Speaker System with Spacers, Max Power:100 Watts x 2. Injection Moulded Carbon Fibre Cone, Frequency Response:45Hz-30KHz, Mounting Depth: 50mm