What characteristic makes locks with collars or cone-shaped covers difficult to operate without a specialized tool?

Locks with collars or cone-shaped covers are designed with unique shapes that inhibit standard unlocking methods. The specific geometry of these locks often prevents the use of traditional keys or simple tools that one might typically use to manipulate them. This purposely complex design is aimed at enhancing security, making it difficult for unauthorized individuals to open the lock without the appropriate specialized tools.

While the internal mechanism's complexity can contribute to security, it is the distinctive shape that primarily complicates the use of common unlocking methods. The other considerations, such as cost or materials, do not directly affect the operational difficulty without the right tools.