A primary battery includes a cathode having a non-stoichiometric metal oxide including transition metals Ni, Mn, Co, or a combination of metal atoms, an alkali metal, and hydrogen; an anode; a separator between the cathode and the anode; and an alkaline electrolyte.

A shaver head comprising a blade assembly having one or more blades for cutting hair in a shaving direction; a skin adaptor extending from an outer periphery of said blade assembly and having a skin adaptor surface configured to be in contact with a shaving surface; a coil assembly, the coil assembly being configured to be transitioned between an active state and an inactive state and to generate an electromagnetic field in the active state. The electromagnetic field can be configured to cause pili muscles in the shaving surface to contract in order to expose hair of the shaving surface so that the hair is cut by the blades of the blade assembly.

A shaver head comprising a blade assembly having one or more blades for cutting hair in a shaving direction; a skin adaptor extending from an outer periphery of said blade assembly and having a skin adaptor surface configured to be in contact with a shaving surface; a coil assembly, the coil assembly being configured to be transitioned between an active state and an inactive state and to generate an electromagnetic field in the active state. The electromagnetic field can be configured to cause pili muscles in the shaving surface to contract in order to expose hair of the shaving surface so that the hair is cut by the blades of the blade assembly.

A razor cartridge includes a plurality of razor blades installed in one direction of a cartridge frame, and a trimmer installed in the other direction of the cartridge frame, wherein the trimmer includes a trimming blade seated in a seating groove formed in the cartridge frame, and a trimmer cap coupled to both sides of the cartridge frame so that the trimming blade is fixed.

A razor cartridge includes a plurality of razor blades installed in one direction of a cartridge frame, and a trimmer installed in the other direction of the cartridge frame, wherein the trimmer includes a trimming blade seated in a seating groove formed in the cartridge frame, and a trimmer cap coupled to both sides of the cartridge frame so that the trimming blade is fixed.

An integrally formed rigid razor blade made of martensitic stainless steel includes a cutting edge portion, a base portion, and a bent portion. The cutting edge portion extends along a cutting edge portion axis and has a cutting edge at one end. The base portion extends along a base portion axis. The bent portion is intermediate the cutting edge portion and the base portion. The blade has a concave face and an opposed convex face. An average radius of curvature of the concave face of the bent portion is between 0.5 millimeters and 1 millimeters.

An integrally formed rigid razor blade made of martensitic stainless steel includes a cutting edge portion, a base portion, and a bent portion. The cutting edge portion extends along a cutting edge portion axis and has a cutting edge at one end. The base portion extends along a base portion axis. The bent portion is intermediate the cutting edge portion and the base portion. The blade has a concave face and an opposed convex face. An average radius of curvature of the concave face of the bent portion is between 0.5 millimeters and 1 millimeters.

An integrally formed rigid razor blade made of martensitic stainless steel includes a cutting edge portion, a base portion, and a bent portion. The cutting edge portion extends along a cutting edge portion axis and has a cutting edge at one end. The base portion extends along a base portion axis. The bent portion is intermediate the cutting edge portion and the base portion. The blade has a concave face and an opposed convex face. An average radius of curvature of the concave face of the bent portion is between 0.5 millimeters to 0.57 millimeters.

An integrally formed rigid razor blade made of martensitic stainless steel includes a cutting edge portion, a base portion, and a bent portion. The cutting edge portion extends along a cutting edge portion axis and has a cutting edge at one end. The base portion extends along a base portion axis. The bent portion is intermediate the cutting edge portion and the base portion. The blade has a concave face and an opposed convex face. An average radius of curvature of the concave face of the bent portion is between 0.5 millimeters to 0.57 millimeters.

A shaving razor adapter used to attach a shaving razor cartridge to a razor handle. The razor cartridge has a pair of distally positioned arc shaped receiving regions and a camming surface. The adapter engages the razor cartridge with a pair of outwardly facing arc shaped bearings for mating into said pair of arc shaped receiving regions of said razor cartridge. The adapter has a recess and a pair of detents for receiving and engaging the handle. The handle has a biasing member to engage the camming surface of said razor cartridge.