Why do pianos have the red strip at the top of the keys?

[salim]

What's the reason behind it? Tried googling but other stuff comes up..

[indianajo]

The felt is there to keep the keys from bouncing up if you hit them too hard or some kid pulls up on them..  Nothing else holds them down but the mechanism on the hammer end and gravity. 
Both my pianos that felt strip is brown. 

[huaidongxi]

one or two high end brands use royal blue felt for that buffer.

[salim]

Ooh, alright thanks ^^