Which of the following is a swivel that allows a socket wrench to reach around obstructions?

A universal joint is a type of joint that allows for the transmission of torque between two shafts that are not in the same alignment, which makes it particularly useful in applications where space is limited or there are obstructions. In the context of using a socket wrench, a universal joint enables the wrench to articulate and pivot, allowing the user to access fasteners that are situated in difficult-to-reach areas. This pivoting capability is critical for reaching around obstacles without the need to remove surrounding components.

In contrast, a socket adapter is designed to allow different sizes of sockets to be used with a single drive size, while a sockets extender simply lengthens the reach of the socket, providing access to deeper or more recessed fasteners. A speed handle is a tool that allows for quick ratcheting motions but lacks the flexibility and joint feature of a universal joint. Thus, the universal joint stands out as specifically designed to address the challenge of reaching around obstructions effectively.