Cross-slot screws for mounting fans on radiators. The special UNC thread, from the non-metric unit system, has been specifically designed for radiators from the USA or the United Kingdom. They form an intermediate size between M3 and M4 threads. With the flat, slightly larger head, the screw sits well and can also cover larger holes that may be present with various grille types. Thus, they not only serve a structural purpose but are also visually appealing and look nice after installation. The thread length has been kept deliberately short to prevent damage to the fins from over-tightening during the installation of the fan, grille, or housing with the radiator. However, we would like to emphasize checking the length of the screw before installation! Important: These screws should only be used in combination with a 25 mm fan, as the screws are too long for narrower fans and can damage the radiator. If a fan grille is used with narrower fans (20 mm), they will fit again. Compatibility: XSPC, Swiftech, and others. Technical details: Material: brass, black nickel plated; Shaft length: 40 mm; Thread length: 8 mm; Head height: 3 mm; Wrench size: 6 mm. Delivery includes: 4x Phobya screw UNC 6-32 x 40 cross - black nickel. Caution: Over-tightening can damage the radiator, so please pay attention to the correct length of the screws. These screws may not be suitable in every case.