BDH H2SQ is a dual-rail sim racing shifter combining independent H-pattern and sequential mechanisms in a single unit, switched via a mechanical mode-selector collar. The H-pattern mode uses 8 configurable gear gates with both shafts moving in unison, while sequential mode locks the secondary shaft for defined actuation points with an adjustable, double-locking detent gauge. Construction uses a precision-machined HE260 aerospace-specification aluminum chassis with high tensile steel components, PTFE-lined spherical bearings, self-lubricating bronze bushings, and radiused 303 stainless steel gate pegs. Shear parts are EN8 high carbon steel, rated to 40 tonnes. The gear knob uses a WRC-spec nylon Quaife-style design. Gear detection uses BDH's proprietary contactless Hall effect sensors with a built-in processor running custom firmware, connecting via USB-C (2m cable) with no external power supply required. It measures 300 × 200 × 150mm and weighs 4kg. Mounting uses standard M8×1.25 points with T-nut compatibility and 360-degree positioning, with an optional sandwich adapter plate available; the gear knob thread (M10×1.5) supports third-party knobs. It's backed by a lifetime warranty, including for commercial use.