This is an ALPS Snatch Block with a hook attachment, designed for heavy-duty lifting and pulling operations. The block features a hinged side-plate (which gives it the name "snatch block") that can be opened to quickly and easily insert a wire rope or cable onto the sheave (pulley wheel) without needing to thread it through the end.
Key Features and Use:
Function: It is primarily used to change the direction of a pulling force (like a winch cable) or to increase the pulling/lifting capacity of a winch or hoist (often doubling the effective power by creating a compound pulley system).
Construction: Typically made of forged or cast steel for high strength and durability, painted green in this case.
Components: It consists of a heavy metal frame, a single rotating sheave.