Hardness
The most important aspect of the shaft is the type of wood it's made with.
Granadillo is an extremely strong wood from Belize; in fact, it's one of the strongest out there.
Granadillo has a Janka hardness of 2700 lbf, which to most people doesn't mean much.
The Janka scale measures the wood's resistance to indentation and overall "hardness".
This isn’t a measure of durability in terms of snapped shafts, it’s a resistance to dents, but there is correlation.
In comparison, here are other woods you may have heard of:
Janka Hardness (lbs) --- Dent Resistance
Granadillo is harder than all of these, which is important in the game when you want to lay a hard check into your opponents and maintain a dent-free shaft.