10TW3-D4
10-inch (250 mm) Subwoofer Driver, Dual 4 Ω

12TW3-D4
12-inch (300 mm) Subwoofer Driver, Dual 4 Ω

10TW3-D8
10-inch (250 mm) Subwoofer Driver, Dual 8 Ω

12TW3-D8
12-inch (300 mm) Subwoofer Driver, Dual 8 Ω