Retention peg for custom Solid State Drive (SSD) holder

https://plus.google.com/u/0/photos/p...1074?icm=false Image related. I am to make a SSD cart holder. I need some guidance. My employer wants me to make a bump that causes a minimal amount of friction so as to keep the cart in place. I have tried many different kinds of bumps (See image:circle thing is one of them) and they have been rejected. Is there an optimal kind that anyone could reccomend.

I can’t open the image, maybe it’s just me?

From what I understand you want a friction fit. So it depends on what material you are using. ABS is flexible, so it might be good for what you are doing, and in which case I would design it such that only one side of a semi circle us connected to the frame, and the other side is free to flex out if the way while still creating pressure on the drive.