My "incubator" is a plastic container with some moist pearlite, no holes in the lid. Very technical stuff here

(no holes in the lid allow the perlite to stay moist MUCH longer than if it had holes; i have not had to add any water to it for 3-4 months with no sign of having to add any anytime soon).
PS.....yes, i open the lid every day, or every other day so they can breath