Backplane BPN-SAS2-846EL1

Interface 6Gb/s SAS (SAS-2)

Number of drive slots 24 x 3,5"

Compatible drives SAS up uo 6Gb/s, SATA up to 6Gb/s

SAS Expander Chip

LSI SAS2X36 (source)

Overview of LSI SAS Expander ICs