原子筆通常呈圓形,中心通常有一個孔。它至少有一個平坦的承重面。它由天然或合成的珍貴或半珍貴寶石(紅寶石、藍寶石等)製成。它適用於精密儀器、儀表、計時裝置、鐘錶等。
used with screws 20000740, 20000687, and plate assy 400193 special features, aircraft mechanical clock 6645-00-076-3050 end item identification, to 5n11-2-11-33 reference data and literature, jewel part name assigned by controlling agency