mawkie
C&R Whisperer
Shame that diopter sights for K31s are so expensive (approx $350) 'cause they're the way to go. Every set that goes to auction on Ebay always has a stiff bidding war. The chinese have made a cheap knock-off copy but I wouldn't spend my hard earned money on it. From what I hear the quality is dubious at best. Not what you want in a diopter!