At 13 defence, I have access to the slayer helmet and addy gloves, but also because nature spirit gets 1-13 def, but its mainly the addy gloves and 10 def required for slayer helmet, which when imbued is the same defensive stats as a rune full helm, so 13 def for a 40 def helm practically and when imbued gives a small bonus to range and magic attacks, as well as making training through slayer a lot easier and viable