This product is either discontinued or we cannot get that from suppliers.
Qnap RAM-4GDR4K1-SO-2400, 4 GB, Speed PC4-19200 (2400 MHz), DDR4, DIMM Type 260-Pin SO-DIMM, 1.2 V.
The 4GB DDR4 2400 MHz SO-DIMM Memory Module from QNAP. Delivering speeds up to 2400 MHz, this module is a memory upgrade designed to improve your system's overall responsiveness and ability to handle data-intensive applications.