This is the original 1 GB PC2-6400 RAM stick from my iMac.
If you have a recent (2008 revision) 20" iMac, this is a cheap and easy way to boost performance by doubling memory to 2GB.
$15, located in Stittsville.
Subject line is wrong now, as the latest iMac is the 2009 revision which uses different memory.
*** corrected by AdminMan