Detail this asset from Unity Store: Original Link
This is a paid asset, but now you can download Pool, Trigger, Constrain Bundle Free.
Pool, Trigger, Constrain Bundle v7.1.0
New pricing from March 2016! Was $59.95. May not be a permanent change. Save over 25% with this bundle of core, high-performance tools and get your 2D or 3D prototype up and running in no time, and scale to full production without hassle.
* PoolManager: Preload and pool objects for re-use with PoolManager, the most popular and battle hardened Instance pooling solution.
* TriggerEventPRO: Get easy access and information to and from objects in range of other objects and construct behaviors using components and events with this robust framework.
* UnityConstraints: Drop on simple behaviors, such as Smooth Look-At (use any axis), Billboard to camera and Transform (like parenting without the hierarchy) constraints with UnityConstraints.
If you were to buy these individually, it would cost $80.
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