An oral care implement comprising: a body comprising: a gripping portion comprising a shoulder; a stem extending from the shoulder along a longitudinal axis (A-A); and a boss protruding from an outer surface of the stem, the boss comprising a locking rib section having an undercut surface that is axially spaced from the shoulder and a positioning rib section extending from the locking rib section to the shoulder, the undercut surface circumferentially protruding from a first side surface of the positioning rib section; a replacement head comprising: a tubular sleeve comprising a cavity and a proximal edge defining an opening into the cavity; a slot in the tubular sleeve comprising a locking slot section spaced from the proximal edge and an entry slot section that extends from the proximal edge to the locking slot section; and a locking tab comprising a distal edge that forms a first lateral wall of the entry slot section and an upper edge that forms a bottom wall of the locking slot section; wherein the tubular sleeve is detachably coupled to the stem in a locked state in which: the stem is located within the cavity of the tubular sleeve, the positioning rib section is located within the entry slot section, and the locking rib-section is located within the locking slot section, the upper edge of the locking tab engaging the undercut surface of the locking rib section; characterized in that the locking rib section extends along a first rib axis (D-D) and the positioning rib section extends along a second rib axis (E-E), wherein the first rib axis (D-D) is oriented obliquely to the second rib axis (E-E). a body comprising: a gripping portion comprising a shoulder; a stem extending from the shoulder along a longitudinal axis (A-A); and a boss protruding from an outer surface of the stem, the boss comprising a locking rib section having an undercut surface that is axially spaced from the shoulder and a positioning rib section extending from the locking rib section to the shoulder, the undercut surface circumferentially protruding from a first side surface of the positioning rib section; a gripping portion comprising a shoulder; a stem extending from the shoulder along a longitudinal axis (A-A); and a boss protruding from an outer surface of the stem, the boss comprising a locking rib section having an undercut surface that is axially spaced from the shoulder and a positioning rib section extending from the locking rib section to the shoulder, the undercut surface circumferentially protruding from a first side surface of the positioning rib section; a replacement head comprising: a tubular sleeve comprising a cavity and a proximal edge defining an opening into the cavity; a slot in the tubular sleeve comprising a locking slot section spaced from the proximal edge and an entry slot section that extends from the proximal edge to the locking slot section; and a locking tab comprising a distal edge that forms a first lateral wall of the entry slot section and an upper edge that forms a bottom wall of the locking slot section; a tubular sleeve comprising a cavity and a proximal edge defining an opening into the cavity; a slot in the tubular sleeve comprising a locking slot section spaced from the proximal edge and an entry slot section that extends from the proximal edge to the locking slot section; and a locking tab comprising a distal edge that forms a first lateral wall of the entry slot section and an upper edge that forms a bottom wall of the locking slot section; wherein the tubular sleeve is detachably coupled to the stem in a locked state in which: the stem is located within the cavity of the tubular sleeve, the positioning rib section is located within the entry slot section, and the locking rib-section is located within the locking slot section, the upper edge of the locking tab engaging the undercut surface of the locking rib section; characterized in that the locking rib section extends along a first rib axis (D-D) and the positioning rib section extends along a second rib axis (E-E), wherein the first rib axis (D-D) is oriented obliquely to the second rib axis (E-E). the stem is located within the cavity of the tubular sleeve, the positioning rib section is located within the entry slot section, and the locking rib-section is located within the locking slot section, the upper edge of the locking tab engaging the undercut surface of the locking rib section; characterized in that the locking rib section extends along a first rib axis (D-D) and the positioning rib section extends along a second rib axis (E-E), wherein the first rib axis (D-D) is oriented obliquely to the second rib axis (E-E).