This study explores a novel vibration control device which consists of an improved inerter with enhanced inertance, conceived to boost structural performance during dynamic events. By embedding a traditional inerter within a rhombus truss structure, the device leverages a geometrical amplification effect, based on the diagonal ratio of the truss, to increase its inertance. The inerter connects to one diagonal of the truss while external excitation acts along the opposite diagonal, allowing the system to achieve higher inertial responses. The study first assesses a traditional inerter model without the truss to establish baseline inertance properties. Then, experiments analyze the improved inerter under varying sinusoidal excitations, comparing two setups: one replicating standard inerter behavior and another with amplified inertance. Through these configurations, the study examines whether theoretical models of inertance align with experimental data and introduces theoretical models to better predict device behavior. These findings suggest that amplified-inertance inerters could significantly enhance structural control, offering new possibilities for vibration management in engineering applications.