Melrose Performance Polymers are shock absorption materials for wheelchair casters designed for use in customizing Frog Legs suspension caster forks (see separate entry). Frog Legs caster forks replace a wheelchair's existing caster forks with shock absorbing hinges that use Melrose Performance Polymers to absorb the impacts that a wheelchair's casters encounter. The polymers are cylindrical, and they fit in the Frogs Legs fork where they absorb vibration to reduce shaking and bouncing in the frame of the chair. The polymers are available in three densities, each or which is a different color: soft (black), medium (orange), or firm (red). By selecting a specific density, the caster forks can be adjusted to the wheelchair's usage or the user's weight by changing the density of the shock absorbing polymers. They are sold in pairs. COLOR: Black, orange, or red.