So, for yo-yos you have the bearings, you have the fixed axles, you have the transaxles, you need a response though, you need something on the yo-yo that's actually going to physically grab the string and pull it up to you. In most cases in many of the traditional yo-yos they we're just flat, there was no response to them and the reason this was because is the gap used to be really tight with the fixed axle, the yo-yo is already moving a little bit slower and there is a little more to grab onto it. As we got into the transaxles and as we got into the metal ball bearings, because they're spinning so freely you need a little more of something to grab onto the string to pull the yo-yo back to your hand. So the first kind of response they figured out is something called starburst response. If you can see on this yo-yo, you've got all these raised plastic right around where the bearing sits. It kinda looks like a star bursting, I guess you could say, as there's little spots coming all the way around like that, it looks like a sun, this is what actually grabs onto the string and pulls it back to your hand. So starburst was the first kind of response they figured out. It worked really well initially, you know with the basic ball bearing yo-yos, but overtime people wanted something a little bit different something like that could grab the string a little bit better and what they came up with was something called a friction sticker. This is a sticker coated with rubber, you know it's the little white and black and some spots where the rubber is actually worn off but the whole idea is it's a sticker, it's a peel off sticker, it goes right onto the side of the yo-yo and the rubber around here is just enough that it can grab the yo-yo, return it to your hand and it's really great for some of the more wider ball bearing areas where you need a little more something to grab the string. They've also started using an O-ring. This is just your basic O-ring that you could pick up at a hardware store. It fits right into the groove of the yo-yo. This is what I prefer because with an O-ring, they'll sleep for a much longer period of time, you can really get it to grab the string when you want to, you never have to replace these. I've used them forever and never had the need to get a new one. O-ring response has really helped keep yo-yos going in terms of maintenance wise, you never have to do a thing. You just keep playing with it and you're good to go. That's the basic response types there is to yo-yos.