The Bussmann series TL-25PK4 is a pack of 4 time-delay, Edison base plug fuses. The medium duty TL fuses are ideal for residential motor circuits in kitchens, workshops, garages and utility rooms. Plug fuses thread into receptacles. Two types of threaded fuses are available: Edison base (brass) and rejection base (porcelain). The two are not interchangeable. TL and SL medium-duty fuses are regular duty fuses. T and S are heavy duty fuses for more demanding applications with high inrush currents. Plug fuses provide a compact and economical method to prevent electric motor damage, reduce downtime and lower maintenance costs by opening when an overload is present. When used for residential branch circuit protection, fuses are typically located in the main fuse panel.