8pc Thick Baffle Speaker Mounting Bolts 1/4-20 x 2.5″ Long Black Oxide +Tee-Nut
1/4-20 x 2.50” Socket Head Cap Screw with T-Nut (8pc Set). The t-nuts are inserted on the backside of the baffle and are generally about 7/16" so take that into consideration. Hardened, grade 12.9 bolt set.