These muslin "Tea" gowns are available in two weights of cotton fabric.
The lightweight version is softer, cooler, drapes nicely and folds down to a convenient size for travel. It's a good choice for sleeping.
The regular weight is heavy enough that you can't see through it. With age it becomes softer. The opaqueness makes it a good choice for lounging and you can wear it around the house or in your yard.