inches is imperial . 1/8" = ~3mm the 15mm fans are 20dBa and 80's are more suited as the 120's dont fit we enough to provide air flow over each drive. the opening is about 430mm... ish, whcih means that the Hd's are almost entirely covered, except for the top bay, but i may sacrifice the top bay for some sort of electronics of some kind (more on that later). the drives are about 80mm wide so 2 rows of 5 fans give almost total coverage, whereas 120's only give partial coverage to 80% of the drives. If the fans are too loud some sort of 7V setup'll be used instead and each pair of fans will be abel to be turned on or off seperately. The 7V idea is fairly attractive because of the in/out flow rates, with 8 or 10 80mm fans at the front the airflow coming in is potentially huge, compareed to the possible extraction amounts. As with many things, this is currently going through some consideration as for fans on the back next to the mobo. More when ive though about it. The plexi idea is great, but provides no means of getting the air into the front of the case, and the cables will get in the way and make them noisey and inefficient. so they have to be mounted in the door at the front. I did pick up the sheet metal this afternoon and ive started work on the hinge for the door, its a pain and ive already designed, made and screwed the first one up. So, 2nd time lucky... as usual. Its really starting to get to me that few things actually go right first time. but thers nothing i can do about it, i spent so much time planning in the past that nothing gets done as everything gets redisnged with minor tweaks but it normally does get sorted. Going to try and do more work this weekend but not hopeful. probably early next week for more progress shots.