Screw in T Nuts are less likely to spin over time than the 4 pronged hammer in T Nuts.

Round base t-nuts are used in a lot of commercial climbing gyms because of their strength and the minimal effort required to install. You can insert them by hand into the predrilled holes in your climbing wall. There are 3 holes in each t-nut which allow you to fasten a couple screws into the wood from behind the wall. These screws will keep the t-nut from spinning and from popping out when you try to fasten a hold to the wall.

3 zinc plated screws are included with each t-nut ordered. Threads are 3/8".  Sleeve length is 10.5 mm.

If you are willing to spend the extra money you'll save a lot of time!