whats this bush called? (not hairy)

hi all,had my wheels off today to clean them and for a clueless look in and about that area,brakes seemed fit and free,equal wear,springs and shocks all good,but i did notice though,the rubber pictured looked ever so slightly perished,don't think its a major issue as yet but i like to keep on top of things so i would appreciate it if some one could tell me what i need to ask for and if its upgradable when i replace it/them,cheeers


7747992158_992e6a8260_b.jpg
001 by scott1532, on Flickr

7748005500_18a9fa2648_b.jpg
002 by scott1532, on Flickr
 
thats the lower rear wishbone bush...

unless its ripped and torn away its fine - they do flex a lot and can look "worn" but as long as they are still bonded to outer and inner sleeves they are fine