Flexible Rubber cones are durable for many repeated uses. These missiles are the best of all missile line carriers. Constructed with Heavy-Duty stainless Steel hardware and Polyurethane blow cups, this ultra-tough projectile will perform flawlessly for you time and time again. Used to pneumatically install pull line into conduit runs, the missiles are fast and efficient, easily blowing through out-of-round Duct with hand blower tools. The cups, which are resistant to solvents, oxygen, ozone and sunlight have an outstanding flex-life, guaranteed to outlast other elestomers on the market today. Fast and efficient for long runs with easy pullback.