just to add on wat kenshin is replying. the first 4 digits its ur machine type, the next 3 is the sub-model. and yes. if u happen to buy extension warranty. make sure to check the details. is ur warranty upgrade by us (service center) or by the reseller. meaning after our system detects ur machine is out of warranty, but if a customer claims to have extended the warranty with the shop, it means u have to contact the shop. i have a case last year, a customer bought a SL400 from i think harvey (iirc). he bought extension of warranty from there. but my system checked it is only 1 year standard carry in warranty. but he got i think 2 yrs extended. so after checking, his additional 2 yrs is not covered by us, but by his reseller... so guys out there i hope this helps in preventing u from coming up & down; making urself frustrated too. lastly, i will try my best in any problems u face to my ability. have fun using the thinkpad.