Most of the Duncan Hard core yo-yos require some form of sticker response. Both friction stickers and silicone stickers are available to customize your style of play.
The Duncan Silicone Stickers provide long lasting response and are slightly less aggressive than regular friction stickers for today's advanced string tricks.
These are the larger 13.7mm version and can be used on most wide bearing yoyos. Duncan Hard Core yo-yos work optimally with 12mm stickers.