... ,reusable,biological. 2.preserve water and store nutrients SAP for agriculture, water absorbent polymer:can swell hundreds of times in water ... soil or substrate to preserve water and nutrionts,small plants, agriculture and non-soil transportaion.There are 4 sizes,WRA-0 ... "case study"for details)Packing:20kg/bag25kg/bag SAP for agriculture, water absorbent polymer, water retain agent