BK/S500-1.25-R is a fast-acting glass tube fuse designed for circuit protection in low-voltage applications. It features a 1.25 A nominal current rating with a 250 V voltage rating and an interrupting capacity of 35 A at rated voltage. The fuse has a typical cold resistance of 0.096 O and a typical melting I-T value of 0.84 A², providing reliable overcurrent protection with fast response characteristics. The 5 mm × 20 mm physical dimensions with silver-plated endcaps (for ratings up to 125 mA) and nickel-plated endcaps (for higher ratings) ensure compatibility with standard fuse holders. This fuse is designed to IEC 60127-2 standards and carries multiple international agency approvals (cURus, CSA, CCC, BSI, VDE, SEMKO, IMQ), making it suitable for consumer electronics, industrial equipment, and telecommunications applications requiring fast-acting overcurrent protection.