CPR Aquatics RSS24DX retrofit overflow box with backing. Open box, New. The shrink wrap is falling apart, which is why I'm calling it open box. $50 OBO cash.
Specs:
• Black acrylic Box with backing only.
• 18 5/8" L x 4 1/4" W x 5 1/4" H
• Rated by CPR for tanks up to 300 gallons.
Local pickup only in Bay Ridge, Brooklyn, $50 OBO cash