GATELY AUDIO Shield series 12" subwoofer.  

Outside Diameter 12.52"
Cutout Diameter 11.125"
Mounting Depth 7.125"

2.75" 4 layer voice coil

Y35 7.48" Ferrite Motor

GATELY shield embossed dustcap

1000-1200 watt RMS 

 Weight: 28.3 lbs

Model: Shield 12 D1
f(s) = 36.27 Hz
Q(ts) = 0.6779
V(as) = 17.8 liters (0.6284 cubic feet)
SPL = 82.23 dB SPL 1W/1m
Nominal Diam. = 0 mm (12 in.)
R(e) = 2.165 Ohms
Q(es) = 0.7864
Piston Diam. = 257.2 mm (10.12 in.)
SPL = 87.9 dB SPL 2.83 Vrms
C(ms) = 4.7e-05 mm/N
Z(max) = 15.7 Ohms
L(e) = 4.797 mH at 1kHz
Q(ms) = 4.915
BL = 16.04
n(0) = 0.1029 %
M(ms) = 410.1 grams

Model: Shield 12 D2
f(s) = 36.34 Hz
Q(ts) = 0.6697
V(as) = 19.52 liters (0.6892 cubic feet)
SPL = 82.71 dB SPL 1W/1m
Nominal Diam. = 0 mm (12 in.)
R(e) = 4.204 Ohms
Q(es) = 0.7766
Piston Diam. = 257.2 mm (10.12 in.)
SPL = 85.5 dB SPL 2.83 Vrms
C(ms) = 5.1e-05 mm/N
Z(max) = 30.55 Ohms
L(e) = 8.117 mH at 1kHz
Q(ms) = 4.867
BL = 21.46
n(0) = 0.115 %
M(ms) = 372.6 grams

Model: Shield 12 D3
f(s) = 39.06 Hz
Q(ts) = 0.7354
V(as) = 18.07 liters (0.6382 cubic feet)
SPL = 82.81 dB SPL 1W/1m
Nominal Diam. = 0 mm (12 in.)
R(e) = 6.238 Ohms
Q(es) = 0.8721
Piston Diam. = 257.2 mm (10.12 in.)
SPL = 83.89 dB SPL 2.83 Vrms
C(ms) = 4.8e-05 mm/N
Z(max) = 39.8 Ohms
L(e) = 10.84 mH at 1kHz
Q(ms) = 4.691
BL = 24.72
n(0) = 0.1178 %
M(ms) = 348.1 grams