Three sided Internal Overflow is 6"x 8", has a 1" drain bulkhead only. Used for tanks up to 24" tall.
This overflow is incorporated into the middle of the end or back of your tank ( PLEASE TELL ME WHERE ). It is used in conjunction with a Wet-Dry Trickle filter.
The overflow is black by default unless YOU specify otherwise. All bulkheads are included and all bulkhead holes are pre-drilled. Overflow also comes with a cover and a black-out panel.
See Internal Overflow in out Library Section for more information.