Nerf Ultra Sonic Screamers darts make a whistling sound as they fly through the air! Stock up with this refill pack of 20 Nerf Ultra Sonic Screamers darts for Nerf Ultra blasters. These ground-breaking Nerf Ultra darts feature a whistle tip, Aerofin technology, and Nerf Ultra foam -- their advanced design and performance delivers extreme distance, accuracy, and speed. Take your game to the next level with Nerf Ultra blasters and darts! Nerf Ultra darts work only with Nerf Ultra blasters. Eyewear recommended (not included). (Blasters each sold separately.) Nerf and all related properties are trademarks of Hasbro.