This item is suitable for Alu-case of Raspberry Pi B+ (sku.359560 361735) - You can plug directly it into the GPIO of Raspberry Pi B+. - Why don't open a hole to install fan? We think that the beauty is important when we begin to design this item. Firstly We have to extend the lengnth of case if install fan via nut and screw Thus length to width ratio is uncoordinated. Secondly for some people the fan is not required so it very ugly if you remain the four mounting holes. You can tight the fan using double side tape. Don't worry the double side tape is not tight. Please see the follow picture. in fact It can bear the total weight of case and PI. Or you can use the glue to stick the fan to the case.