Ever since harbinger made the stupid decision to stop making their original hook I tried many different hooks on the market and nothing comes close to your product. Most of my upper body workouts are done with cables or body weight exercises using your hook and it is excellent for the following reasons:
1 The curve of the hook Is not too short like others hooks. It very adequately fits my metal handgrips and often will fit other gym hand pieces as well without being too long.
2 the velcro wrist wrap works great in that it is thick , wide and long enough to give a very strong and well padded support and the padding is generous and thick . When used properly, your hooks allow for a great deal of the desired isolation of a given body part because They very effectively take the effort away from hand and forearm activation so grip strength does not become the major factor in how much a muscle can be worked. And with me i do strength training so this is critical for my results.
Those were the two most important things i can tell you about your hook design.
Over time, and for me that means weeks, i notice a change it the support and it might very well have to to with the heavy weights i use but if you interested, i have a design idea that has developed over the time I’ve been using your hook, let me know if you would like to discuss my thoughts on that