Sealey-3-Piece-Spark-Glow-Plug-Torque-Limiter-Set-3-8-Square-Drive-Sealey-SX0371-Modern-day-spark-&-glow-plugs-are-built-to-exacting-tolerances-as-are-the-engines-they-are-fitted-to-Over-torque-the-plug-&-this-can-lead-to-stretched-threads-incorrect-air-gaps-broken-inductance-coils-or-ceramics-incorrect-positioning-of-spark-in-the-cylinder-&-ultimately-to-a-poorly-performing-or-even-damaged-engine-The-SX0371-prevents-over-tightening-of-spark-plugs-&-glow-plugs-&-ensures-gara