The anvil and spindle have a small diameter (3mm x 10mm) for measuring Splined shafts, slots, and keyways. Igaging 0-1" digital quick micrometer absolute origin speedmic snap lever action gage igaging absolute origin speedmic uses the absolute encoding technology in which the sensor memorizes and traces an absolute origin zero position. Quickly measure with Super high precision lever activated - fully opens and closes in less than one second! linear moving sensor provides accurate and reliable measurements IP65 coolant proof measuring range: 0-1"/0-25MM Carbide tipped spindle resolution: 0.00005"/0.001mm accuracy: ±0.00015"/0.003mm fixed thimble. Spc/USB data output available (not included) search Amazon for item: b00inl0ba2. Ball attachment included. Case included 2 years warranty.