The ALUMINUM frames moving forward will ALL be PAINTED WHITE 

C-310A aluminum basement insert - Monarch replacement with expander / adapter and dual pane glass.

Size: 31 x 36-3/16 + Expander = 36-5/8 egress

Columbia Series C310A Aluminum basement window replacement insert with insulated glass. 
Maintenance free, energy efficient. 
Easy, 1 minute installation.
Requires no tools for installation; uses high tensile steel spring clips to secure the insert in the opening.
Expander allows for use in most concrete basement walls with poured-in-place steel buck frames. 

Color: White Aluminum finish standard

Comes with removable chain pulls for easy removal for emergency escape purposes 

The Monarch was slightly smaller than Columbia and the Expander is added to the bottom of insert
The expander creates a 5/8\" thick leg that fits into the Steel Buck Frame.

Fits in buck with 1/2 to 5/8 inch drop-down (see third image)

Standard Sizes
31 x 12-3/16 + Expander = 12-5/8
31 x 16-3/16 + Expander = 16-5/8
31 x 20-3/16 + Expander = 20-5/8
31 x 36-3/16 + Expander = 36-5/8 egress window

Note: Basement inserts with expanders are used with Steel Frames, Aluminum Frames do not need the adapter. 

Priced and sold each.

Resources: 
Article: How to Replace Basement Window Inserts
Video: How to Replace Basement Window Inserts