... DTM312A, DTM312B, DTM315A, DTM315B, DTM322A, DTM322B, DTM325A, DTM325B suits the measurement with target and prism.SPECIFICATION: ModelDTM312A,DTM312BDTM315A ... .0mAdditive constant0Objective lens apertureφ48Resolving power3.75”Field of view1°30’(26m/1000m)Stadia proportion100Reticle illuminationProvidedAngle measurement ... with compensator B without compensator DTM 300 total station SURVEYOR INSTRUMENT