Keep your 21700 battery packs safe and properly spaced with these flame retardant spacers. Designed to prevent short circuits and reduce the risk of fire spreading, these spacers are essential for secure battery assembly. Each pack contains 3 spacers with size options to fit various 21700 cells. Main Features: Made from flame retardant plastic for enhanced safety Prevents potential battery fires from spreading Maintains proper spacing for 21700 cells Size Options: 21.2mm – Fits most Samsung, LG, Murata 21700 cells 21.7mm – Fits most Lishen  Easy to install and reusable Specification: Material: Flame retardant plastic Compatible with: 21700 batteries Quantity: 3 spacers per pack Size options: 21.2mm / 21.7mm