20" 34Sl Pro-Guard Chisel C-Loop Chain. It offers 78 drive links and meets ANSI standards, ensuring safety and reliability. This chain is compatible with Husqvarna models 33, 38, 40, 42, 44, 45, 50, 51, 55, 57, 133, 140S, 154, 234, 238, 240, 242, 254, 257, 340, and 444. It comes with a limited lifetime warranty for peace of mind.