This is a rare, long discontinued Samurai Elcan sight.

This review below is literally for this actual sight, as it was recently bought from Arnie himself: 

http://arniesairsoft.co.uk/reviews/samurai_eclan/samurai_eclan_review.htm

Very good condition: some chips on one of the rail screws. Crystal clear sight within a chunky, well built rubberised body. Very weighty. Sadly not with the original box.

Reasonable offers will be considered: please feel free to ask, haggle, etc., The worst I can say is 'no.'