This product is either discontinued or we cannot get that from suppliers.
Synology Ram RAMRG2133DDR4-32GB, 32 GB, DDR4 SDRAM, 1.20 V, Speed 2133 MHz, ECC, Registered, 288-pin, FF DIMM.
RAM capacity can be expanded on selected Synology NAS servers for boosted performance and responsiveness under high system loads. To ensure the optimum durability and compatibility.