Well the pictured link is a classic master link, not what most would call a Missing Link. the difference is that a master link is for a non der chain, a 1/8" wide chain/cog. Usually found on single speed or internal geared hubs (as there haven't been 4 speed freewheels for a LONG time). A Missing Link is actually a series of connecting links for der chains, 7.8 -5.9mm widths (IIRC). The Missing Links don't have a circlip that slide onto the pins to hold things together. (The master links are too wide for freewheels and cassettes). Connectors Archive » KMC Chain Here's a link to the KMC website which describes some of these links. Andy.