The tailpiece is the part of the lock that extends from the outside housing (where you insert your key), through the bolt, to the interior thumb turn. Its rotation is what mechanically turns your lock. Because you’re replacing the original bolt with Level Bolt, you need an adapter to connect the original tailpiece to your new bolt.
Level Bolt comes with three tailpiece adapters, to fit almost every American Standard deadbolt.
If you have a Defiant brand deadbolt, order a type-D tailpiece adapter.
When installing Level Bolt, be sure to choose the right tailpiece adapter for your door. If you choose the wrong one, you may notice some play when you turn the key or paddle (in other words, you may notice that the key or paddle moves a few extra degrees before moving the bolt).
Read How to install Level Bolt for specific instructions.