No matter what your likes and dislikes. You're sure to love these flashing spikes. Wear some while you play your blues harp. They're made of soft rubber so the spikes aren't sharp. Spike bracelets are cool. Spike bracelets are keen. They come assorted with peach, purple, blue and green. Specifications: Length: 9.1 in. Width: 0.9 in. Depth: 0.62 in. LED Colors: Blue, Green, Red, Yellow Batteries: Batteries for this product are NOT Replaceable.