Replacement ignition coil module kit designed as a direct replacement for the listed part numbers and compatible with the specified chainsaw models. This kit restores ignition and stop switch function so the saw starts and shuts off reliably. Key benefits Restores spark and starting reliability by replacing a faulty ignition coil. Includes stop kill switch and spark plug for a complete basic in one kit. Direct replacement for part numbers 503717901, 503620203, 544018401, 503901401 for straightforward fitment. Saves time and reduces downtime with a single solution. Compatibility Fits chainsaw models: Husqvarna 50, 51, 55, 254, 257, 261, 262 XP, 266, 268, 272 XP. Verify model and part numbers before ordering to ensure correct fit. What is included 1 Ignition coil 1 ON OFF STOP KILL SWITCH 1 Spark plug Function and attributes Ignition coil: generates the voltage required for spark at the spark plug to ignite the fuel mixture. Stop kill switch: simple on off switch to interrupt ignition and shut the engine down when needed. Spark plug: standard replacement plug included to complete the ignition circuit. Designed for direct replacement of the listed part numbers and to match the original mounting and electrical connections. Typical applications scenario: a failed ignition coil in a chainsaw that will not start or that misfires during operation. Field service: Carry the kit for quick roadside or jobsite repairs to minimize interruption to cutting tasks. Maintenance: Use as part of routine service for rental or fleet saws to keep equipment in working condition. Notes Confirm compatibility with your specific model and part number before installation. Basic hand tools are normally sufficient for installation; seek professional service if unsure about electrical connections or installation steps.