SIGMA PRO Connector makes the snap together on chain assembly faster without the riveting removal tool. Sigma Pro’s pinhead groove interlocks positively with the top plate, providing remarkable riveting strength, making Sigma Pro Connector as strong as any other links in the chain, and no issues with the quality for shifting. TAYA DHT pin applied on Sigma connector with self-lubricant & extreme durability is as same as any link of other DHT chain model. There are millions of Sigma Pro Connectors in use every day around the world for over 26 years providing its reliability.