A hair clipper or cutter is provided with an adjustment slider that adjusts the gap between an inner and outer blade. A yoke is attached to the inner blade. The adjustment slider may be configured with preset gap lengths and may be adjustable before, after, or during a hair cutting operation. A T-guide couples the adjustment slider to the inner blade to slidably move the inner blade relative to the outer blade. The yoke, inner blade, outer blade and/or T-guide may be magnetized to create an attractive or repulsive force between the inner blade and the outer blade. In some embodiments, the yoke is not metallic. The magnetized yoke may be a non-conductive magnet carrier (e.g., plastic) or conductive material (e.g., ferromagnetic).