ophthalmic A/B scan: 1.CE, ISO13485, ISO 9001 2.USB 2.0 ... small, light, compatible 4.fast delivery time ophthalmic A/B scan #CAS-2000B: Main configuration:USB 2.0 compatible,Ultrasonic videoing ... calculation: Holladay, Hoffer-Q, SCDK, SRK-II, SRK/T, HaigisB-Scan model: 60 degree mechanic sector scanDetect Depth>=50mmImage storge: 10 framesGray ... A/B scanner, you may order our cas-2000C model.Thanks.