QQI Test Pieces - Miniature QQI Test Pieces - Miniature Print QQI Test Pieces, Miniature Quantitative Quality Indicators, also known as notched shims, are magnetic particle test pieces with artificial defects. Verifies the direction and relative strength of magnetic fields. CM230: Miniature QQI KSC4-230 (CX4-230), four circle with cross on one shim (to be cut by user into four separate shims. 30% notch, 0.002” (51µm) shim thickness. Request for information