Single adjustable post (SAP). One narrow (0.65mm at apical tip, 1.0mm at coronal end), universally sized, end-tapered post size that fits the modern, conservative RCTs at the apical area. Usually this is achieved without drilling. Allows the clinician to adapt the slender fiber post to flared canals with the vertically sliding conical sleeve when needed. Sleeve is the same fiber-reinforced composite as the post and slides on when the post is inserted, converting the pointed, parallel post into a custom-fitted post.