i-node or block size?

from ADD Home version 11 userguide:
I-node density is determined by specifying the number of bytes per i-node. Usually, the default value is 4096 bytes per i-node.

Ok, let's spell it with dash. I googled a bit and it seems that most frequent inode sizes are 128 or 256 bytes. However there are structures called 'blocks' that have a typical size of 4096 in ext2. So, is it inode or block size that ADD can change?