This product is either discontinued or we cannot get that from suppliers.
G.skill Tridentz 16g Kit F4-4400C19D-16GTZKK, 16GB (8GBx2), Dual Channel Kit, Speed 4400MHz, 1.35V, Unbuffered, Non-ECC, Non-Fan.
Building on the strong success of G.SKILL Trident series, Trident Z series represents one of the world’s highest performance DDR4 memory designed for overclocking enthusiasts and extreme gamers.