question on bulkheads

[blackthunda77]

ok so i posted this in the diy but i need help asap......

ok so i bought these bulkheads....i noticed on the gaskets that on one side its flat but on the other side it has 2 little ridges....so......how do i install these, which side does the flat side go on and which side does the ridged part go on?

 

[blackthunda77]

anyone?

 

[RicksReefs]

ridged side to the bulkhead, flat to the glass.

the ridges take up any uneveness in the molding of the BH.

 

[blackthunda77]

thanks