Available in Unbreakable, iFlex, and Clear Blend, the JP Bullets are specifically designed to work with the JP90 Handheld Injector.tcs® Unbreakable An extremely resilient, high-performance nylon material for fabricating removable partial dentures and unilaterals. Unbreakable, lightweight, durable, flexible, repairable, relinable, and stain resistant. Low water absorption.