Dimensions of 120mm case fan-diameter or diagonal?

[absxiith]

I want to install two of these-

http://www.flipkart.com/cooler-master-90-cfm-blue-led/p/itmd7q4fcdvw3ujg?pid=COLD7Q4DF73WMYF4&_l=He6KBVf4L1udh%20tb3uTX2w--&_r=Hm9ZHljbShvygMoLNKykVA--&ref=b69b6530-af22-4946-8a34-e2d6a09f661a

My question is-do 120x120x25 mm dimensions mean 120mm diameter or diagonal?I measured my present case fan and it is 90mm along diameter and 120mm along diagonal.My PC-

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01815020&tmp_task=prodinfoCategory&cc=in&dlc=en&lc=en&os=2093&product=3929100&sw_lang=

However,I could not find any 90mm case fans,only 80mm and 120mm.Am I doing something wrong?Any help would be sincerely appreciated.

 

[GI_JONES]

120mm is the width of the fan housing. The most common sizes are 80mm, 92mm and 120 mm

 

[absxiith]

Ok,that means the square within which the actual fan is placed,right?Will a 120mm fan fit in my case which probably has a 92 mm fan or only a 92mm fan will fit?Am asking because 92mm fans arent available but 120mm fans are.

 

[GI_JONES]

sure they are: http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007998+600035583&QksAutoSuggestion=&ShowDeactivatedMark=False&Configurator=&IsNodeId=1&Subcategory=573&description=&hisInDesc=&Ntk=&CFG=&SpeTabStoreType=&AdvancedSearch=1&srchInDesc=

 

[absxiith]

I can't order from Newegg as they do not ship to India. Also,can I fit an 80mm fan instead of my stock 92mm fan coz 80mm and 120mm fans are easily available here.

 

[GI_JONES]

I dont have that pc, so I dont know what will fit.