They looked an ok size on the following sire that shows how to get at them they look to be about 3 inches long or so, but are pretty powerful. I will make a knife sharpening jig which will use one to secure the knife to the ret to hold it steady while sharpening *(plus have a backrest to keep the knife j. Position too). The 3 inch magn e t should be perfed ft size for that
Here’s a ,ink if you wanna see how to remove them
https://www.instructables.com/Rare-Earth-Magnets-From-Old-Hard-Drives/
How old of a hard drive?
My old hard drive is barely 3 inches total!..............