There is a water resevoir in the bottom of the reptibator. Fill that up with water, or moisted the sponge material you set the eggs on. Either one will increase the humidity.
Pros of the reptibator-lightweight, easy to find ready to use.
cons- sometimes the temps and humidty gauge is a little off not a huge deal to me though, can only fit 2 or so bp clutches in it but several geckos or whaterver.