Front scoop skid

Hello, I am 16 and new on hear, I am currently building my first robot, just a ram bot at the moment, and was wondering what a part was called. The part in question is like the top of a ball point pen but a larger on to use instead of a nylon skid at the front of my scoop, if anyone knows what this part is called and/or were I could by some from, I would be very grateful.
Thank you

Ball transfer unit?
Technobots do some

ahh, thank you so so much, i knew something like that existed and had been typing all sorts of weird and wonderful things into eBay to try and find it, Thank you