NAGYS CUSTOMS UNIVERSAL 12" SPEAKER ADAPTER
 
These have a depth of 2" and an overall depth of 2.5" Easily cut down to whatever depth you need.
 
Tons of options with this from saddle bags, trike trunks, freewheelers, tour packs, etc. Just shape how you want them to fit.
 
Made from durable polyurethane.
 
*Sold as Singles
 
Designed for Drop Rail or Custom Bags