Ok these are not all speed certified, and there really is no such! You willl notice in the pic they say 32x!
there are now 40x burners on the market so these will not work in them!
TDK media is the worst i have ever used, they would not read in some cd-rom's while my prime peripherals read fine in all (and the prime's are as generic as they come!
For those of you with a local fry's electronics they always have a 50 pack spindle of better quality media for only $9.50 and you get them when you need em no need to wait or pay for shipping ocasionally they put em on sale for $7.00! these also are 32x media!