Compact Zoom tube corresponds to M Plan APO series (M Plan APO2.5X,M Plan APO5XSB,M Plan 10XSB,M Plan APO20SB,M Plan APO50XSBS,M Plan APO100XSBS),Magnification ratio is 6X. In case of mounting objective lens(CV-10-M26), the WD is 92mm and magnification range is 0.7X to 4.5X| MSZ-APO