出生地 |
Fujian China (Mainland) |
Contentdiameter4-15diameter15.1-50N(Newton's rings)-2~-5-2~-5N(Surface accuracy)0.3~1.00.3~1.0center thickness±0.015±0.02~±0.1Outer diameter±0.005±0.01~±0.05Partial core30′60′~180′depth±0.01±0.015appearance60/40~20/1060/40~20/10