Listed below are the deadbolt specifications you should be looking for:
Outer slip ring should be free moving when NOT installed.
Outer slip ring should contain a tempered or hardened interior ring. (slip ring shouldn't be hollow)
Bolt should be 1" thick with a 1" throw (bolt extended).
When installed, bolt should lock into place when extended. You should not be able to push the bolt back by hand.
Bolt should be constructed to include a hardened steel core.
Lock cylinder should be constructed of 100% brass (some lock manufacturers use a combination of brass and plastic).
Screws that anchor rear thumb-turn plate to front lockset should be heavy-duty at least ¼" or larger in diameter.
Deadbolt face should be 2 pieces (outer slip ring with separate lock face - some manufacturers may join both pieces
Deadbolt should be of a 6 or 7 pin construction. (Available ONLY through locksmiths and locksmith supply houses)
Deadbolt should contain pick-proof pins. (Available ONLY through locksmiths and locksmith supply houses)
When mounted to the door surface, the deadbolt face should be able to sit flush to the door to help defeat crowbar
FACT: It is well known among Law Enforcement Agencies (criminals know it too) that a poorly constructed deadbolt lock can be easily opened by applying brute force with a pair of ViceGrips®.
FACT: A deadbolt that includes an outer ring that slips with a tempered or hardened inner ring provides MAXIMUM SECURITY against ViceGrips® attacks.
FACT: A Key-In-Knob Lock does not offer anywhere near enough protection. Have a deadbolt installed for the maximum protection of your property.
FACT: A lock is only as good as the door it's mounted on.
FACT: All locks are not created equal and unfortunately you only receive the degree of security that you are willing to pay for.
FACT: If you do not have a deadbolt lock installed on your door you are asking for trouble. Criminals know that Key-In-Knob locks are quickly and easily defeated. Install a quality deadbolt for peace of mind and help to keep your belongings safe and secure.