locking system of two adjacent caps

Locking system of a first plug (14) and a second plug (15) adjacent each plug can adopt a closed position wherein the plug (14, 15) is held in contact with a mouth (11) and an open position wherein the plug (14, 15) is spaced from the mouth (11), the locking system comprising a lock (21) having a body (22) rotatably mounted about an axis ( a), a first bolt (23) and a second bolt projecting from the body (22) and angularly offset relative to each other, the latch (21) being rotatable between a first locking position wherein the first bolt (23) engages the first stopper (14), the second bolt being free, and a second locking position in which the second bolt engages the second stopper (15), the first bolt (23 ) being free.