Clasp With Safety Side Catch
Filigree Clasp with Safety: Clasps with wider tounges and side safety clasps are the most secure for slide bracelets. The extra protection of the side safety is common on many quality clasps on finer made bracelet items. Most of the tounges similar to the picture are die-struck which is traditionally the best for the "spring" needed to keep the clasp tight and durable for many years.
Lightweight Button Clasps
Button Clasp: Many slide bracelets and starter slide bracelets are sold with a lightweight clasp that has no side safety. These were originally designed for pearl necklaces. While durable they do not offer the same security that a clasp with the side safety does.