Sight sold on Ebay ?

Hi
Could someone please tell me what I failed to see, that made this sight so special ?

Thanks Terry

http://www.ebay.co.uk/itm/Lee-Enfiel...vip=true&rt=nc

A) Do Not Know
B) Look at the feedback scores the 0000's one backed off leaving the lower ones to inflate the price it also had that magical word Sniper T in the add yep thats a sure recipe that that particular sight was destined to be placed on a T.......