I purchased the madbull fishbone set because I needed a space and the package came with a two fishbone style spacers, one rubber bucking, and one silicone bucking. The rubber bucking was a little to thick to get into my hop up, so I used the silicone one. Supposably, silicone buckings have better compression, but wear out quicker. After installing it in my gun, I tested it out with KSC .25s and the the gun was WAY more accurate. I was amazed that just a bucking could increase the accuracy that much. For 13 bucks you get two buckings and two spacers. Time will tell how long they last, but they definitely perform great. Buckings usually have to "break in" and it was very accurate out of the box.
I would definitely recommend the madbull fishbone bucking set. I have far less fliers than before and if I do get a flier, it is only off by like 2 inches compared to like 4. lol
just thought I'd share that.