This clip is an accessory for the Zalman ZM-WB4 GOLD which gives AM2 compatibility. So if you wish to use a ZM-WB4 GOLD CPU water block with an AMD AM2 processor, you need this clip! Note that this clip is not needed if you are using a ZM-WB4 PLUS or ZM-WB5 water block, because they are both compatible 'out of the box'.