Andersen Narroline Top and Bottom rail foam weatherstrip for Double Hung Window.

Fits on the bottom of the lower sash and top of the upper sash
3/8 x 3/8 square foam, vinyl wrapped. Sold by the piece 42" 

Use clear silicone or vinyl adhesive to hold foam in place.
See miscellaneous service parts and materials to purchase silicone.
Weatherstrip can be easily cut with household scissors. 
Note: Window sash Sides(stiles) have a slot in foam, sold by the window height.

Related Andersen Parts: All previous discontinued colors are replaced with Black:
1631510 - Weatherstrip - Foam/Top and Bottom Rail - White
2731510 - Weatherstrip - Foam/Top and Bottom Rail - Terratone
1152914 - Weatherstrip - Foam/Top and Bottom Rail - Sandtone