I first bought 1 x 1Gb RAM from this company for my MacBook Pro but then decide that 2 x 2 Gb would work better and ask to exchange my first bought items. This was no problem and I send back the 1 Gb RAM for which I never received a refund. In the mean time I had already paid and received the 2 x 2Gb RAM sticks. Once installed it constantly crashed my computer. I tried several times with several possibilities (installing one original stick with one newly bought stick etc), no of the times my computer worked, it always crashed. I searched the internet for help and found a company Crucial who also sold RAM sticks and bought another pair ( 2x 2 Gb) from them and this time it worked perfect and still does. I know the first pair of RAM sticks I bought from Funky Giraffe are useless and they refuse to refund me although I have already resend them the very first RAM stick I bought. They only replied to my complaint with instructions on how to install and clean the RAM sticks but nothing works. They are selling absolute rubbish. The ones I bought from Crucial are not only working perfect but also look new.