What type of keg is described as having a one-way disposable mechanism?

The one-way disposable mechanism characterizes a Keykeg, which is designed specifically for one-time use and does not offer the ability to be cleaned or refilled after the beer has been consumed. This keg is notably different from traditional stainless steel kegs, which are designed for multiple uses and can be cleaned and serviced. The Keykeg employs a unique bag-in-a-keg system where the beer is contained in a plastic bag, and as beer is dispensed, the air is not allowed to mix with the beer, reducing the risk of oxidation and maintaining freshness.

In contrast, other keg types like stainless steel kegs and party pumps are reusable and come with different dispensing mechanisms involving valves and fittings that allow for multiple uses. While pinlock kegs are also designed for refillable use, they use a different closure mechanism that allows for easy connection and disconnection of gas and beer lines. Thus, the Keykeg is distinct in its functionality as a single-use vessel, providing operational benefits particularly in situations where minimizing cleaning and maintenance is advantageous.