This anchor is an excellent choice for both solid and hollow block concrete. Its main advantage is that it allows the bolt to pass through the anchor. This is advantageous because you are not forced to drill an exact depth of the hole or have an exact bolt length. Climbing holds differ in thicknesses which means so does the length of thread on the bolt that sticks out the back of the hold.
The Simpson Strong-Tie® Hollow Drop-In Anchor (HDIA) is an internally threaded, flush-mount expansion anchor for use in hollow materials such as CMU and hollow-core plank, as well as in solid base materials such as brick, normal-weight and lightweight concrete.
Material: Die-cast Zamac 3 alloy shell with carbon-steel cone