I made my own. Cheap clip on sunglasses spray painted the shooting eye lens black and drilled hole at place of exact alignment with my eyesight path. Started with 1/16th in hole and went larger in very small steps until I found size hole that works best. Total cost, $6. Been using them for years. Another method is to take black electrical tape and punch hole with proper sized pin punch and apply tape patch to lens of regular glasses.

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Lost in Penn's Woods