Reference 6.3 is a 3-way component in DLS Reference series with: 

• 16.5 cm (6.5") bass,
• 6.3 cm (2.5") midrange
• 20 mm (0.8") tweeter T20.
• Filter boxes with selectable tweeter level in three steps and midrange level in two steps.
• Grilles are included.

Specifications

• Woofer size: 16,5 cm (6,5")
• Tweeter: T20, 20 mm (0,8") silk dome tweeter
• Midrange size: 6,3 cm (2,5") UP 2.5
• Power handling capacity: 60 W RMS / 90 W max
• Impedance: 4 ohm
• Frequency range: 60 - 20 000 Hz
• Sensitivity: 93 dB (1W/1m)
• Crossover: Filter box with 12/6/12 db slope
• Crossover point (Hz): 550 Hz / 4000 Hz
• Size of filter box: 145 x 85 x 45 mm ( 5,71 x 3,35 x 1,77")
• Outer diameter of woofer: Woofer: 165 mm (6,5"). Mid: 100 mm (3,94")
• Magnet size: Woofer: 80 mm (3,15"). Mid: 65 mm (2,56")
• Mounting depth: Woofer: 63 mm ( 2,48"). Mid: 25 mm (1")
• Mounting hole: Woofer: 146 mm (5,75"). Mid: 82 mm (3,23")