This platform is meant only for use with the included inset, which is an extension of the platform that fits inside a power rack.
This platform is made for doing cleans, snatches and deadlifts. Using a high quality lifting platform means that users are lifting on a perfectly flat and safe surface. The increase in confidence that provides means that it's only a matter of lifting the weight that's holding them back.
An inset is included. It's the piece that extends the platform to fit inside your rack.
(For the York STS Triple Combo Rack you'll want to buy two platforms, one with the #54250 inset and one with the #54253 inset)