 They can also be used where low-distortion signal transmission is needed, like on PCB (board-to-board) interconnects, or in IC testing sockets where additionally many mating cycles are required.They can be used discretely as a signal/ground contact or for Electromagnetic interference (EMI) protection.When a mating array for multiple contacts is needed, like for BGA or LGA IC packages, Fuzz Buttons can be placed in thru-holes in an insulated piece of material, such as dielectric plastic.