What is the difference between soft gel nail and hard gel nail?

Hard gel enhancements are also known as "buff off nails" whereas soft gels are also known as "soak off nails". The difference is mainly to do with the removal technique. Hard gels are non-porous and so cannot be removed by any other method than buffing it right down. Soft gels are able to be soaked off with acetone which is much easier. However, soft gels tend to be more lightweight and flexible, which some people prefer as it seems more natural, but it does mean they tend not to last as long as hard nails which are stronger.