Originally Posted by Panthers007

They are meant to be used with the chain on the bike at it's lowest stress - small front/small back cog. Push the black meniscus all the way away from you on the left. Insert the right end metal-peg into a inner link (thinner link) and the left hand peg (the one under the black meniscus) into an outer link (thicker link). It's supposed to be a tight fit. Push the meniscus back toward you until it stops, and take your reading.