These are cut logs that were used for shiitake mushroom cultivation for 3-5 years. They are domestic Konara oak logs. How about using them for insect breeding? As shown in the photos, there are variations in size (diameter, length), the extent of mycelial growth, and individual differences. They have been dried in the sun for several days before being listed. Insects may be present. If you are concerned, please heat-treat them before use. ◯ Size Length: Approximately 14 cm to 15 cm Diameter: Approximately 8.5 cm to 10 cm 12 pieces per set ◯ Hardness It is soft enough for a toothpick to be inserted near the bark, but the center is solid and hard. * The logs used for shiitake mushroom cultivation have good mycelial growth throughout, including between the bark, and are well-rotted. * Can also be used as food for larvae of beetles, etc. * Some people use them as perches for adult insects. ◯ Notes * Because the wood is fully matured, some parts of the product may be prone to crumbling, so please handle with care after receiving it. * Occasionally, some Quercus serrata wood may be mixed in. * Since they have not been treated for insects, please heat-treat them before use if you are concerned. * Due to the nature of the product, changes in size and texture, cracking, peeling of the bark, and the appearance of mold and moss may occur over time. * Shipped via anonymous delivery. * This is a private seller, not a business. I cannot answer specialized questions. Please refrain from purchasing if you are looking for perfection. Please purchase only if you agree to the above. Please ask if you have any questions.