Difference between these two hard drives ?

[Ash0787]

https://www.overclockers.co.uk/seag...64mb-cache-hdd-oem-st4000dm000-hd-281-se.html


https://www.overclockers.co.uk/seag...64mb-cache-hdd-oem-st4000dm000-hd-337-se.html


both are ST4000DM000 but one is 5 pounds more and has more reviews

I have one that is probably around 18 monthes old, which of the two is it likely to be ? I want to get the same one preferably

 

[Ash0787]

Ok thanks, I wondered whether it was a revised version of the drive or something with less platters