POLICE yesterday offered a $50,000 reward for information leading to the arrest and prosecution of robbers who made off with spectacle frames worth more than $1.5 million from a Yau Ma Tei company in July last year. Two men posing as customers threatened staff members with knives before tying them up and ransacking the premises. A third man stood guard outside. Any person who has information should call the police hotline on 527-7177.