The fuse elements used in most distribution cutouts are tin or silver alloy wires that melt when subjected to high enough current.
Mechanical tension on the fuse link normally holds an ejector spring in a stable position.
Each fuse holder typically has an attached pull ring that can be engaged by a hook at the end of a fiberglass hot stick operated by a lineworker standing on the ground or from a bucket truck, to manually open the switch.
For applications where the switch is likely to be used to interrupt power manually, a "load break" version is available that has an attachment to quench the arc.
This design allows for the interchangeable use of cutout bodies and fuse holders manufactured by different vendors.