Don't install a lock in a hollow metal door without a Door-Core™. The Door-Core™ metal door reinforcer is a fast, economical, and dependable means of reinforcing a hollow metal or hollow wood door at the point where a cylindrical lockset is to be installed.
Sold in packs of 5.

More Information Below:

Features:

• May Be Used for Cross Bores of 1 1/2″ to 2 1/8″
• May Be Used on Hollow Wood or Metal Doors
• May Be Used on Doors 1 3/4″ Thick or Thinner
• Eliminates Disengaged Latch Bolts or Dead Bolts
• Centers and Supports the Bolt
• Eliminates Binding Caused by Misalignment
• Prevents Foreign Material From Fouling the Lock
• Increases Security, Prevents "Icepick" Attack
• Can be used by Commercial and Government Agencies