The name is really very accurate: the Light Tights weight in at less than 100g. And they're tights.
Using HyActive – a fibre which allows them to transport moisture but not get saturated – the Light Tights are enhanced with a touch of elastane for totally unrestricted movement. Also adding to the comfort are the flatlocked seams, so they don't chafe.
Because they're so effective at shifting moisture, they have the nice side effect of drying extremely quickly.