Coming in different types, live green moss packs are a living thing, that with the right fresh water and light will thrive in a rainforest type set up, with warmth and humidity. It is suitable to use with almost every species, and should really be around 24 - 32C, with a high humidity of over 50%.
Moss is a living breathing part of your vivarium, and so will help keep humidity levels up, and also add fresh oxygen into the enclosure from photosynthesis. The moss is prepacked and sealed with moisture, keeping it self-perspiring whilst sealed, and it will freshen up when put into fresh light in the vivarium, though may appear a little brown straight from delivery.
Carpet Moss comes in sheets of around 20 x 20cm, though each piece is different and they will vary. They can be placed over the flooring of vivariums, and also around logs and branches, to encourage growth over them. The Cushion Moss come in 5-6" sections, to add in small patches around the vivarium, to allow to grow together if you wanted. These may have brown tints on arrival, though will brighten up in fresh air and good lighting, allow a week for moss to thrive again.