... protrudent Indenter Design, suitable also for internal and external testing.2.Advanced Digital Rockwell Hardness Tester Testing on Surfaces difficult to reach ... HRH,HRK, HRL,HRM,HRP, HRR,HRS,HRVLoad dwell duration: 2~50s, can be set and storedResolution :0.1HRDisplay:High definition ... spare steel ball1/4″ball indenter and spare steel ball1/2″ball indenter and spare steel ballφ225 anvilφ150 anvilStandard ...