This is a 10X DIN-standard objective lens for compound microscopes. It features achromatic color-correction, and plan field-correction. Features & Specifications: Magnification: 10X NA: .25 Optical Working Distance: 5.84mm Thread: RMS Mechanical Tube Length: 160mm Cover Glass Thickness:0.17mm Color Correction: achromatic Field Correction: plan Immersion Medium: none Nosecone: fixed