A level comprising: a level body formed from a first metallic material, the level body defining a base surface configured to engage a 2. workpiece ; at least one level vial located within the level body ; a cavity located in the level body defining an opening along the base surface , said opening extending substantially perpendicular to a vertical direction ; a magnetic circuit coupled to the level body within the cavity , the magnetic circuit comprising: a pair of metallic structures , formed from a second metallic material, wherein the second metallic material is a ferromagnetic material and is different from the first metallic material; and a permanent magnet located between opposing inner surfaces of the pair of metallic structures ; characterized in that each of the opposing inner surfaces of the metallic structures is a non-vertical, non-planar surface, and the permanent magnet includes a pair of non-vertical, non-planar lateral surfaces each facing the opposing inner surfaces of the metallic structures , wherein the non-vertical, non-planar shape of the lateral surfaces of the permanent magnet engages the opposing non-vertical, non-planar surfaces of the metallic structures such that relative movement between the permanent magnet and the metallic structures is resisted. a level body formed from a first metallic material, the level body defining a base surface configured to engage a 2. workpiece ; at least one level vial located within the level body ; a cavity located in the level body defining an opening along the base surface , said opening extending substantially perpendicular to a vertical direction ; a magnetic circuit coupled to the level body within the cavity , the magnetic circuit comprising: a pair of metallic structures , formed from a second metallic material, wherein the second metallic material is a ferromagnetic material and is different from the first metallic material; and a permanent magnet located between opposing inner surfaces of the pair of metallic structures ; characterized in that each of the opposing inner surfaces of the metallic structures is a non-vertical, non-planar surface, and the permanent magnet includes a pair of non-vertical, non-planar lateral surfaces each facing the opposing inner surfaces of the metallic structures , wherein the non-vertical, non-planar shape of the lateral surfaces of the permanent magnet engages the opposing non-vertical, non-planar surfaces of the metallic structures such that relative movement between the permanent magnet and the metallic structures is resisted. a pair of metallic structures , formed from a second metallic material, wherein the second metallic material is a ferromagnetic material and is different from the first metallic material; and a permanent magnet located between opposing inner surfaces of the pair of metallic structures ; characterized in that each of the opposing inner surfaces of the metallic structures is a non-vertical, non-planar surface, and the permanent magnet includes a pair of non-vertical, non-planar lateral surfaces each facing the opposing inner surfaces of the metallic structures , wherein the non-vertical, non-planar shape of the lateral surfaces of the permanent magnet engages the opposing non-vertical, non-planar surfaces of the metallic structures such that relative movement between the permanent magnet and the metallic structures is resisted. <EOS>