The Compendium of Caraka 8.3.10

8.3.10

syāt karṇikaikā 'agracaturthabhāge mūlāśrite bastinibandhane dve/
jāradgavo māhiṣahāriṇau vā syācchaukaro bastirajasya vā 'api//

There should be one ring at the fourth part from the tip, and two rings at the base to tie the bladder.
The bladder should be of an old bull, a buffalo, a deer, a boar, or a goat.