NOVELTY - The centralizer (1) has a circular hollow structure (2) with an inner surface (4) and an outer surface (5). Several wide ridges (3) extend radially outwards from the structure and axially along the outer surface. The ridges have a recess that extends into the ridge from the inner surface. Each recess has a longitudinal vane (6) which extends radially inwards from the inner surface of hollow ridge. An inner edge (7) of vane is aligned with a circumferential line that follows the circumference of inner surface.    USE - Centralizer for well bore hole, used in centralization system for completing oil, gas, geothermal and other types of wells.    ADVANTAGE - The centralization system assists tubulars to pass over ridges inside well bore and facilitates the rotation of tubulars inside a well bore. To aid installation and reduce the risk of injury to personnel, a threaded hole is provided on the centre of gravity of the centralizer, to allow the attachment of a lifting eye. The configuration of the blades allows the centralizer to slide inside the well bore with the minimum of damage to the filter cake but also generating swirl, enhancing the quality of the cement sheath when circulated. Since the outside radius of the blades suits that of the internal diameter of the well bore, the tendency for the blades to dig-in and damage filter cake which create fluid losses and/or differential sticking issues is reduced. The total flow area is also as large as practicable, in order to reduce differential pressure across the tools when cementing. The blades are pitched through the sinusoidal wave shape because each of the waves is relatively small, hence the pressure on the faces is much less and less torque is developed. The wave form is overall generally axially aligned and any torque effects are reduced or cancelled out.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a stand-off band for well bore holes;    (2) a stop collar for well bore holes; and    (3) a set of cast inserts.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of the centralizer.    Centralizer (1)    Circular hollow structure (2)    Ridge (3)    Inner surface of centralizer (4)    Outer surface of centralizer (5)    Longitudinal vane (6)    Inner edge of vane (7)