Pyle PSI04 - Acoustic Sound Isolation Dampening Recoil Stabilizer Speaker Riser (for Studio Monitor, Subwoofer, Loudspeakers, Shelf Speakers, etc.) 7.5'' x 9.0'', Sold as Single Unit - Walmart.com
Pyle PSI12 - Acoustic Sound Isolation Dampening Recoil Stabilizer Speaker Riser Platform Base (for Studio Monitor, Subwoofer, Loudspeakers, Shelf Speakers, etc.) 22.5'' x 18.1'' - Walmart.com