Just got the excellent weekly newsletter from EliteFTS, excellent grip article by Nick McKinless, Strong Hands for Strong Men. It emphasizes all around lower arm strength. Build the foundation people.
Be sure to sign up for the EliteFTS newsletter, every week there is a bundle of usable strength training info, from CREDIBLE, COMPETITION proven authors.
Aside from heavy duty weight training equipment, they also carry Ironmind's high quality grippers.
And you will NEVER get a "Dear Friend" email. ;)