They are sturdy and excellent for quick attachment to dog leads to tie up outside of local shops and to attach lead to car anchorage points for extra security travelling.
I have used these previously for several years and bought extra for family and friends as they are so useful for quick linkages and are very strong and I have never had one fail despite daily use in all weather. Clearly aluminium doesn't rust but is adequately strong for 'normal' household/outdoor requirements but not for climbing.