Thirty disc cakebox of thick discs, metal-alloy recording layer, maximal 4x coaster-free on LaCie LightScribe Samsung-Toshiba for Macs. Never a bad burn, so no duplicates needed for backups. Advertises 9.7 Mbps compressed optical burns on 30 disc cakebox, but I calculate 5.3 Mbps for CAV uncompressed data at 4x. Slow for automatic backups on LAN (USB on Airport Extreme), where 50 Mbps air, 100 Mbps cable are standard. I turn off Energy Saver & use ice pack to cool PowerBook.