hey two beard a buudty of mine that works at a local archery shop replaced the fiber optics on all my pins--as far as brightness the type of fiber optic makes a difference. when we changed fibers i had a little more fiber protruding from the back of my pins but it wasnt nothing spectacular.go to zenitharchery.com they have a good quality fiber optic.cut old out then put one end of fiber into sight housing at base leave a small amount protruding through the eye in sight pin.take a lighter to cut end and place it near heat, only to ball the end.if the flame touches it it will lose it brightness.they have different sizes.the green will show up the best of all.especially toward dark