Andersen Window - Frenchwood Gliding Doors roller adjustment hole plug in white. 
This plug conceals the hole in that is used to adjust the operating panel tandem rollers located at the base of the operating panel. (1997061 - third picture) 
This part is for Perma Shield patio doors manufactured after 1982. 

Available Colors: 
1997019 - White 
2640002 - Terratone 
0903433 - Sandstone 

Related Andersen Window Parts: 
1997061 - Tandem Roller Assembly with Bracket 
1997062 - Tandem Roller Assembly without Bracket 
1997019 - Roller Adjustment Hole Plug in White 
2640002 - Roller Adjustment Hole Plug in Terratone 
0903433 - Roller Adjustment Hole Plug in Sandstone 
2573620 - Hole Plug - Operating/Roller 

Priced and Sold Each

Helpful Links 
Guide to Replacing Rollers in Andersen Sliding/Gliding Door. 
Video: How to Replace Rollers in Andersen Sliding/Gliding Door.