A desktop computer's motherboard documentation mentions 240-pin DIMM slots. On this motherboard, what kind of DIMM is used?

DDR3 DIMMs are made up of 240 pins. DDR4 and DDR5 DIMMs have 288 pins but are not interchangeable and feature notches (module keys) in various locations to prevent the incorrect modules from being installed into a motherboard. SODIMMs are laptop RAM rather than desktop RAM.