They are the engine room of the forward pack and win the ball in the lineout so without them a team is almost impotent. Rugby writer Steve Hepburn looks at the locks in the All Blacks.
Two veterans, a newcomer, and a steady improver.
The All Blacks look set to have all bases covered in the locking department for the World Cup.
In Ali Williams and Brad Thorn the side has two veterans, with Thorn having been in professional sport for near on two decades, and still chugging away successfully.
Williams has battled back from a couple of years on the physio table after badly damaging his Achilles.
At the start of the Super 15, Williams admitted he was rusty and that was sure how he looked.
His jumping in the lineout was not bad but his work around the field was not quite there and he struggled to make any physical impact.
Former All Black Ian Jones said although Williams had played better of late, he believed the Crusaders duo of Thorn and Sam Whitelock was the leading duo.
"I just believe the work he [Whitelock] does around the field means he has pushed ahead of Ali Williams," Jones said.
"His work-rate is really high and he does a lot of good work at the breakdown. We don't need another ball runner in the pack, we've got plenty of those, and he just gets stuck in."
Jones said Thorn's age should not be taken into account and his conditioning was wonderful.
"Plus he is a great guy to have in the team off the field. Just a complete professional and he will revel in something like the World Cup."
Thorn and Boric will compete for one locking spot with Williams and Whitelock the other.
But with injuries occurring in the loose forwards, one or even two of the locks may be called upon to get into the loose.
Whitelock looks like the prime candidate to wear the No 6 jersey.
The locks
Ali Williams
Age: 30
Test caps: 66
Physical: 115kg, 2.02m
Two years away in the wilderness because of Achilles injuries, he has returned and is ever so slowly finding his form of old.
Brad Thorn
Age: 36
Test caps: 51
Physical: 114kg, 1.96m
The veteran who just keeps on trucking. His ability around the field will be a key if the All Blacks are to be successful.
Sam Whitelock
Age: 22
Test caps: 18
Physical: 114kg, 2.02m
The youngster in the side, Whitelock burst on to the scene last year, mixing a high work-rate with some real athleticism around the field.
Anthony Boric
Age: 27
Test caps: 20
Physical: 110kg, 2m
Got over a nagging foot injury and was rated high enough by the selectors to make the squad after playing little rugby.
