Brother Muadh According to a fatwa i possess [and probably everyone also] a fatwa from Mufti Taqi Uthmani: the conditions are: a] water proof i.e. water should not seep through them b] so thick they can stand upright without having to tie them c] possible to walk in them in continuously for at least 3 miles. p.s. i seen this fatwa on akimam.org, muftisays.com and daruliftaa.com so once again i have to agree with Mufti Saheb. Br Muadh, when you said that the normal average Leather socks do not stand upright, just to tell you i have 3 pears of Khuffs all ranging from prices and quality and after i had zipped them....they stood upright. if you have a pair try it out.