Below are the difference between mTECH DRO-2L, TDS-2 and TDS-2i
the DRO2L is a specific model for lathe machine.
the TDS2 and 2i is a general model, with functions more cater for mill.
DRO2L has a buttton for choosing radius or diameter display
TDS2 and 2i display of radius or diameter is done through the setup parameter
DRO2L has a taper calculation function for lathe
TDS2 and 2i has more of the mill fumction, like PCD, linear holes maching...
DRO2L is made of cast metal, so it is hard and solid.
TDS2 and 2i casing is made of high impact plastic, it is strong and does not conduct electricity, making it safe.
DRO2L mounting is made specially for lathe mounting
TDS2 and 2i mounting is more for milling maching.
if your machine is a lathe machine, i will highly recommend you to select the DRO 2L, if your machine is a mill/lathe or you have plan to use the DRO on a mill, i will suggest you choose the TDS2 or 2i.