They don't sink. The largest two or three pieces are tree roots. They are about 43 x 30 x 25 cm. They are quite large. They are all interesting shapes. How about using them for reptile or insect layouts, or for a paludarium? They have been soaked in water for a while and then thoroughly dried. I will check them carefully before shipping, but there may be small insects mixed in. Thank you for your understanding. ADA ADA Horn Wood Aquarium Terrarium Vivarium Paludarium Insects Reptiles Ikebana (flower arrangement) Store Driftwood Wreath Object Exhibition Ceremony Formal flower arrangement Traditional flower arrangement Flower arrangement (Kado) First meeting