Thus, {HEAD ~ the working distance} of {TAIL ~ all} of the microscopes can be easily changed and all of the microscopes will be focused on the new operative field, and the tilt angle of all of the microscopes can be adjusted by merely rotating one collar 
Thus , { HEAD ~ the working distance } of { TAIL ~ all } of the microscopes can be easily changed and all of the microscopes will be focused on the new operative field , and the tilt angle of all of the microscopes can be adjusted by merely rotating one collar
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH