The exciting new usb hd35si 1a is a stylish high quality aluminium disk enclosure with totally silent operation the newly designed aluminium enclosure acts as a built in heatsink effectively reducing heat output of the enclosed hard disk to enhance reliability and lifespan fully plug n play for leading operating systems including microsofttm windows and mactm os x the usb hd35si 1a allows your existing 25 sata or ide hard disk to be fitted quickly and with minimal effort enjoy fast