Dasqua 20 Piece Brass Feeler Gauge for Spark Plugs Non-magnetic gage made from brass. These feeler gauges suit many applications, from checking engine valve clearances to fine-tuning spark plug gaps and aligning mechanical systems with pinpoint accuracy. Their flexibility enables easy access to tight spaces, while the corrosion-resistant brass construction ensures long-lasting performance. Each gauge is clearly marked with measurements in inches. Engineered for mechanics and engineers alike, our feeler gauges guarantee optimal tolerances during assembly or maintenance tasks. Sizes included are 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00mm.