Ring Sling
Styles - Padded - Gives cushioning to wearer and Kid.
https://duropackindia.com/
Unpadded - more straightforward to fix, not as hot.
Open Tail - Licenses wearer to change top and base rails autonomously. Can include the tail as a sun protect/cover.
Close Tail - No free surface to upset everything. Simply have to fix 1 piece.