This is a complete phase contrast kit for compound microscopes. It comes with three phase contrast plan objectives: 10x 40x and 100x three corresponding phase contrast condensers and CT lens. The mounting size of the condenser is 37mm (in diameter). The thread of the Plan objectives is 20mm (in diameter). Features & Specifications: - Phase Contrast: 10X 40X & 100X - Condenser: NA 1.25 - Mounting Size: 37mm (in diameter) - Objective: Plan PH 10/0.25 PH 40/0.65 & PH OIL 100/1.25 (160/0.17) - Lens: 23mm CT - Shipping Weight: 10