More than a post alone, RelyX Fiber Post from 3M ESPE is a complete system, designed to make excellent clinical results easier to achieve. Elasticity of RelyX Fiber Post is similar to human dentin for a lower risk of root fracture due to the "wedge effect". Unique resin composition and equally dispersed parallel fibers lead to superior mechanical strength. Microporous surface allows for additional bond strength through microretentive effects. Excellent light translucency for efficient light cure deep into the root canal. Improved radiopacity is among the highest of available glass fiber posts. Size 1, yellow.