The are a few different designs.
The standard one looks like a large awl — a single metal pointed thin rod coming out from a handle, that you hold in your clenched fist and stab the ice with. It’s a classic feature in horror movies.
Another kind looks like a large fork-like gardening implement, with 5 to 6 sturdy tines coming out of it
On both designs, the handles are quite sturdy, and somewhat weighted, to help you build up momentum.