... vial is made of Acrylic * The precision is 100'+/-10' * Color,green * Name, precision bubble level * No.,RB-MP1809-5C* Size, ... 18*9MM* This vial is made of Acrylic* The precision is 100 ... '+/-10'* The air bubble will be at the middle of the ring on the level table ... the vials according to your requirements(size,precision and so on)