/diy/ - Do It Yourself

I need a long allen key in order to unscrew the heatsink that is fixed to the motherboard in my computer processor. I ordered this one last week and it arrived today, but it is a standard size. Arm length 21mm, body length 61mm. I don't know where the 30mm dimensions comes from in the ad description. Am I missing something here? Did the seller just post the wrong key? I contacted him just now waiting on a response.