Sock nets simply have an open end. You can net up a Koi, proceed to carry the fish in the soft stocking, and then let the fish slip out of the end into the water again. No fin ripping, and very little struggle.
Sock nets have relatively short handles.
Durable and long lasting, no fin ripping and extremely safe fish transport over short distances. Make sure you clean the net in a dilute soap and water solution, rinse very well and air dry if ever used on sick fish.