This doesn't require any drops or strips, it gives you the readings digitally in just a moment. It tests pH, chlorine, salinity, TDS, ORP, and temperature (which are the things that typically get tested for most frequently). Solaxx does recommend calibrating it about once a month. You can see more info about it here:
https://www.discountsaltpool.com/assets/doc/safedip_manual.pdf