Which type of wrench is not typically adjustable?

An adjustable wrench is designed to accommodate various sizes of nuts and bolts by allowing the user to adjust the width of the jaw. This flexibility is what differentiates it from other types of wrenches.

When considering a box end wrench, open-end wrench, or socket wrench, none of these are adjustable in the same sense. A box end wrench has a closed loop that fits over a bolt head and comes in specific sizes, while an open-end wrench has two jaws that provide fixed sizing on both ends. Similarly, a socket wrench utilizes interchangeable sockets to fit onto fasteners, but the socket itself does not adjust in size.

Therefore, identifying an adjustable wrench as the one that is not typically adjustable is logical because its primary design function is to offer that very adjustability, while the other mentioned wrenches provide fixed sizes suited to specific tasks.