Yorkville SA221S Synergy Series Dual 21-Inch Subwoofer — Chuck Levin's Washington Music Center
Dayton Audio HTS545HE-4 Kraken 21" High Excursion Subwoofer with 5" Voice Coil 4 Ohm
MT21A Built-in DSP single 21" Self-powered Subwoofer with Compact Cabinet Box - Buy 21" subwoofer, single 21 inch subwoofer, self powered subwoofer Product on Sanway Professional Audio Equipment Co., Ltd.
RCF SUB9007-AS Active Dual 21" Subwoofer
Warden 21" 3500W Subwoofer by Incriminator Audio® - SSA STORE
RCF SUB-8005AS Single 21″Active High Power Subwoofer – Sonic Circus
Mvp121-- Powered 21 In. Pa Subwoofer - Stage Audio - AliExpress
Eminence NSW6021-6 21" Professional Neodymium Tour Grade Subwoofer Driver
9921b: 1500w to 2500w - 21 Inch Power Tuned Subwoofer - DD Audio
STLF-21120 | 21" Raw Woofer Speaker, 600 Watts Pro Audio PA DJ Replace – Sound Town
21 inch Eminence Tour Grade Replacement Speaker – Eminence Speaker, LLC