If you really want to improve your grip strength, a Rolling Thunder would be a good idea IMO.
Either build one, or order one.
Grippers could be fun. As always, don't go too heavy all the time. The trainer and the #1 used in combination works for most people at first.
Gradually working the #2 into it.
Randall Strossen is a POS for changing the rules of certification on the #3 and #4.
Get this, he changes the rules, makes it much harder to close it, but won't erase past entries.
POS.
YIP
Zack
PS
Yes. I happen to know someone who got screwed out of certification on the #4 due to Strossen's primadonna acts.