A flap bag closes with a fold-over flap that typically fastens with a turn-lock, push-lock, or magnetic snap. The design provides secure closure and a clean front profile. It's also faster to open and close than most zip closures, and provides better access to the interior.
The flap bag as a luxury form traces directly to Gabrielle Chanel's 2.55, introduced in February 1955. Karl Lagerfeld's Classic Flap version (1983) added the interlocking CC turn-lock. The form has been adopted by nearly every major house — the Gucci GG Marmont, Dior Caro, and Louis Vuitton Twist are all flap bags.
Single vs. Double Flap
The Chanel Classic Flap features a double flap: an inner flap that opens on its own (providing access to the main compartment and the iconic burgundy leather interior pocket) and an outer flap with the CC turn-lock. This double-flap design adds security and creates the bag's distinctive thick profile when closed.