The Koken PK3760/6 is a high-quality extension bar set for 3/8" square drive tools—designed and manufactured in Japan for precision and durability. This set includes six extension bars (32 mm, 50 mm, 75 mm, 125 mm, 150 mm, and 250 mm), each with a knurled base for secure handling. Neatly organized in an ABS tray, this compact set delivers versatility across tight spaces or deep socket applications, making it ideal for automotive, industrial, and maintenance work.