The Model F sump is a three-zoned sump that is divided into three sections:

Skimmer section --> Return zone in the center <-- Refugium section

40" x 16" x 16" It is rated up to a 90g - 120g aquarium.
48" x 16" x 16" is rated up to 180g aquariums - contact me for pricing.

• Skimmer zone: 15" wide x 15.5" front to back x 9" deep
• Refugium zone: 12" wide  x 15.5" front to back x 12" deep
• Return zone:  9.5" wide x 15.5" front to back x 8" deep

Bubble Tower included; you need to carefully add live rock rubble to fill the tower about 6" tall to break up bubbles.

Two 1" Slip Bulkheads included to easily plumb sump to your aquarium.

This sump can be plumbed to an aquarium with one or two drain lines.  With one drain, you will need to Tee off the drain line to divert some water to the refugium zone.  With two drains, plumb one drain to the skimmer section; the second drain should be split to drain 50% into the refugium and send 50% to the skimmer zone's bubble tower. 

Here are the installation instructions, to provide some visual guidelines.  It is important that you read these thoroughly: http://melevsreef.com/articles/installing-the-model-f-sump