These are pellets made from crushed and compressed coniferous trees. The coniferous species is pine (species similar to the pine family). Are you having trouble with the mat becoming soggy quickly? These are recommended for beetles and large stag beetles, which are prone to this problem. They expand to about 3 times their volume when they absorb water, but they last longer if you lay them down without adding water and let them absorb insect urine and spilled jelly, rather than adding water to use them. However, there is a limit, so replace them when moisture starts to seep out. Also, for small stag beetles, they tend to dry out too much, so instead of pellets, mist the stag beetle itself about twice a week. They will be shipped in a plastic bag in an 80-size box. Free shipping. Although it says 5kg, we will roughly pack a little more than that.