My grip strength (which is very evident on deadlifts) is pretty weak. What are some things i can do on off days to increase my grip? grabbing onto a chin-up bar and just hanging, or maybe one of those.. i don't know what to call it, but it's a long cylindrical piece of wood with a rope in the middle, with a few small plates on the bottom, that you hold out in front of you and roll up then roll down. (long winded- sorry!)

thanks for any input you guys/gals and provide.