The difference between ISV-100W and ISV-200W are:
The backlight color of ISV-100W is blue, the temperature control range is 77℉~210℉ (25℃~99℃), the size and weight is 16.5x2.75in, 1212g.
ISV-100W manual
The backlight color of ISV-200W is orange, the temperature control range is 32℉~194℉ (0℃~90℃), it adds dry burn protection function (if the heating element temperature exceeds 212F/ 100C it will stop heating automatically), the size and weight is 15.4x2.8in, 1178g.
ISV-200W manual