Did you order your droprail custom saddlebags with 12" inserts but realized that a 10" subwoofer or midbass may work better with your enclosure? We made these adapter plates for that exact situation, made out our beefy 1/2" marine plastic these can be bolted on bonded in. The center hole is offset since we've found that depending on the taper or bodyline of the bag you get your max mounting depth at certain spots. This lets you clock the speaker to the perfect spot. 1 pair