I'm 33, and noticed my grip had become my weak point keeping me from heavy lifts. I've followed Juji and Tom on their channel for some time and finally decided to start focusing on grip training. I didn't know where I was at on grip so I bought the set of 6, along with a few other products, from Grip Genie and incorporated them into the end of my arm days with the occasional grip test for fun on other days.
When the grippers first arrived I could manage a GG3 right off, I was just happy I atleast fell within the intermediate range. A couple weeks after that and I managed to move up to a GG4 and about a month and half after that closed the GG5 for the first time. The GG5 is when it gets real and I still have to be having a good day to close it but it's great to have the goal of the GG6. I'm a gamer (their branding being part of the reason I went with Grip Genie) so having a belt like system and laddered goals is great for motivation. I've noticed deadlifts, pullups and anything that requires good hand strength has become considerably easier now that I can focus on the lift more than the pain in my hands.
The only drawback I've had is how it fits differently in the right and left hand because of coil direction. I've yet to fully close the 5 in my left hand as the red grip cylinder fits closer to the ends of my fingers, but that's just the nature of all grippers that use a wound coil for resistance.
Great product from great guys, and it's surprisingly fun and addicting to try and move up the gripper levels. Maybe one day I'll finally try chalk.