In mid 90s Cerwin Vega introduced a now mythical woofer series called Stroker. It had two spiders and a badass metal ring horned with a stabilising rod instead of a dust cap (
CVI-218S - Cerwin Vega
Cerwin Vega SPCL182 | 3200W 18"" Single 2 ohm Subwoofer
Cerwin Vega Mobile Stroker ST122 Woofer, 1000 W RMS, 2000 W PMPO - Walmart.com
Old School Cerwin Vega Stroker 18" hits 127,1 dB and almost torn my house to the ground! - YouTube
Cerwin Vega User - Philippines - Cerwin-Vega FH18F(STROKER 18) 18" Afterburner Woofer . *18” woofer with Stroker™ technology for increased output and reduced distortion *1600W Power Handling *Stroker™ pole is vented out
Cerwin Vega 15" DVC Subwoofer Dual 2 Ohm 2400 Watts Max Stroker Series – Pricedrightsales