SO-DIMM DDR4
From Amazon
MicroMemory MMXLE-DDR4SD0001 8GB DDR4 Memory Module - Memory Modules (8 GB, 1 x 8 GB, DDR4, 260-pin SO-DIMM)
Compadvance
COREPARTS 8Gb Memory Module For Lenovo
Athema Services
coreparts 8gb memory module for lenovo 2400mhz ddr4 major mmxle-ddr4sd