Bow Spring Centralizer Guide
Bow-spring casing centralizers are also available in multiple styles, including flexible and rigid, welded and nonweld, single piece, and other.

Conventional Bow-Spring Centralizers

Conventional bow-spring centralizers are the most common type of centralizers (Fig. 1). Also referred to as imperial bow, this centralizer type offers curved flexible bows that can expand or compress according to the variations in casing and hole diameter encountered while casing running in hole.
https://www.drillingmanual.com/bow-spring-centralizer-guide/