A bottle for dispensing fluids into a capless filler system, the bottle configured with an elongated smooth neck designed for insertion into a capless filler opening to actuate and displace one or more flapper seals when emptying the fluid into the capless filler. The bottle is sealed with a cap with a first set of screw threads that engages the neck at a top portion with a second set of screw threads on an interior surface of the top portion of the neck. The cap can be a child proof cap. The bottle can be made of plastic that is clear or opaque.