Two problems:
1) The 1/4 20 are too thick to go thru the slots w/o forcing them,and the heads are small(see #2)
2) #10-32 are the right size bolts but the heads so small they go
right thru the soft material of the horn when you tighten them down.We need to find #10-32 with the oversize pan head JBL uses. Even black washers are unsightly.