Harken Air winches feature a set of interchangeable gearing kits that give skippers the flexibility to create a perfect blend of speed and power for each day 's weather and crew configuration. The winches, which feature a nearly empty middle to reduce weight, were designed for trimming sails on AC foiling cats, IMOCA 60s, AC75s, TP52s and similar Grand Prix boats. The hollow middle is a first for sailing winches, as are the changeable gear kits. All Harken Air winch models feature interchangeable first-speed and second-speed options. The wide-diameter drums allow fewer wraps, faster trimming, and faster easing. Standard and counter-rotating versions are available. The 300 model is designed for boats up to 17 m (56'). It features an anodized aluminum drum. All models can be driven by pedestal or handle. The 300 can also be powered by electric or hydraulic motor.